manual usuario fias mhs15

ATOMIC SPECTROMETRY

User’s Guide

MHS 15Mercury Hydride System

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ATOMIC SPECTROMETRY

MHS 15Mercury Hydride System

User’s Guide

Release history

Any comments about the documetation for this product should be addressed to:

User Assistance

PerkinElmer, Inc.

710 Bridgeport Avenue

Shelton, Connecticut 06484-4794

U.S.A.

Or emailed to: [email protected]

Notices

The information contained in this document is subject to change without notice. Except as specifically set forth in itsterms and conditions of sale, PerkinElmer makes no warranty of any kind with regaed to this document, including,but not limited to, the implied warranties of merchantability and fitness for a particular purpose. PerkinElmer shallnot be liable for errors contained herein for incidental consequential damages in connection with furnishing, performanceor use of this material.

Copyright informationThis document contains proprietary information that is protected by copyright. All rights are reserved. No part of this document may be reproduced in any form whatsoever or translated into any language without the prior written permission of PerkinElmer, Inc.or one of its affiliates.

Copyright ©1998–2000 by affiliates of PerkinElmer, Inc.

Produced in Singapore

TrademarksPerkinElmer is a trademark of PerkinElmer, Inc.AA WinLab, AAnalyst, Lumina, and THGA are trademarks of affiliates of PerkinElmer, Inc.

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Registered names, trademarks, etc. used in this document, even when not specifically marked as such, are not to be consid-ered unprotected by law.

Part Number Release Publication Date

0993-5288 A July 2000 Valid for Software Version 6.5

Chapter 1 Safety and Regulatory InformationSafety practices and conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Correct use of the instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Laboratory hygiene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Laboratory ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Safe handling of chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6Waste disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8Handling compressed gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Safety practices for flame operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12Safety practices for mercury/hydride systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14References for laboratory safety practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16Regulatory information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

Chapter 2 MHS 15: Analyzing SamplesSetting up the system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Positioning the MHS 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Preparing the system for analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4Aligning the QTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6Selecting operating mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Performing a measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10Methods development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

Contents

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Contents

Chapter 3 MHS 15: Recommended Analytical ConditionsSafe handling of chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3Recommended conditions for arsenic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5Recommended conditions for bismuth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7Recommended conditions for mercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9Recommended conditions for mercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11Recommended conditions for antimony . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13Recommended conditions for selenium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15Recommended conditions for tin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17Recommended conditions for tellurium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19

Chapter 4 MHS 15: MaintenancePerkinElmer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3Routine maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

Maintaining the flashback arrestor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6QTA maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7Replacing worn parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Chapter 5 MHS 15: Parts and SuppliesParts provided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3Obtaining supplies, replacement parts, and accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4Replacement parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

Chapter 6 MHS 15: InstallationUnpacking and inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3Installing the QTA burner mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4Installing the reactor assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Connecting the inert gas supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6Preparing the reactor assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8

Chapter 7 MHS 15: Laboratory RequirementsOperating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3Gas supply requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Inert gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

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Contents

Chapter 8 MHS 15: System DescriptionIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3Chemical vapor generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

The cold vapor technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6The hydride-generation technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6Literature on chemical vapor generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7

Principle of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11

Chapter 9 MHS 15: Analytical NotesFeatures of the MHS 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3

Sample volume and dilution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3Purge gas function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4Calibration techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6

Chemical factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7

Chapter 10 MHS 15: Translations of Warnings

Index

Customer Service

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Safety practices and conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3Correct use of the instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Laboratory hygiene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Laboratory ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Safe handling of chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6Waste disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8Handling compressed gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

Safety practices for flame operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12Safety practices for mercury/hydride systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14References for laboratory safety practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16Regulatory information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

Safety and Regulatory Information 11Safety and Regulatory Information

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0993-5288 1-1

Safety/Regulatory Information

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Safety practices and conventions

The guide provided with the instrument contains information and warnings that must be followed by the user to ensure safe operation and to maintain the instrument in a safe condition. This advice is intended to supplement, not supersede, the normal safety code of behavior prevailing in the country of operation.

The information provided does not cover every safety procedure that should be practiced. Ultimately, maintenance of a safe laboratory environment is the responsibility of the user and the user’s organization.

Possible hazards that could harm the user or result in damage to the instrument are clearly stated at appropriate places throughout this guide.

Any of the following safety conventions can be used throughout this guide:

This symbol alerts you to situations that could result in personal injury to yourself or other persons.Details about these circumstances are in a box like this one.

This symbol alerts you to the risk of hot surfaces that could cause personal injury to yourself or other persons.Details about these circumstances are in a box like this one.

Caution The term CAUTION alerts you to situations that could result in serious damage to the instrument or other equipment.Details about these circumstances are described in a message similar to this one.

0993-5288 1-3


Correct use of the instrument

Before you install or use your instrument, and in order to get the best results, you should be familiar with all of the instruments in the system and know how to operate them. You should also be aware of the safety procedures in force in your laboratory, especially those concerning atomic spectrometry instruments. Read the guides supplied with the instruments before you start.

If you use the instrument in a manner not specified in the guide, or if you use it for a purpose other than that intended, you may damage the instrument, or compromise your own, or someone else’s, safety.

This instrument should only be operated by persons who are suitably qualified and have received adequate training.

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Operating conditions

The instrument will operate correctly under the following conditions: Indoors. Ambient temperature +15 C to +35 C (+59 F to +95 F), with a maximum

change not exceeding 2.8 C (5 F) per hour. Ambient relative humidity 20% to 80%, without condensation. Altitude in the range 0 m to 2000 m.

You can store the instrument safely under the following conditions: Ambient temperature –20 C to +60 C (–4 F to +140 F). Ambient relative humidity 20% to 80%, without condensation. Altitude in the range 0 m to 2000 m.

When you remove the instrument from storage and before you put it into operation, allow it to stand for at least a day under the approved operating conditions.

Laboratory hygiene Keep the work area scrupulously clean to avoid contaminating your samples

and to maintain a safe working environment. Clean up spilled chemicals immediately and dispose of them properly.

Do not allow smoking in the work area. Smoking is a source of significant contamination and also a potential route for ingesting harmful chemicals.

Do not store, handle, or consume food in the work area.

Laboratory ventilationToxic combustion products, metal vapor, ozone, etc., can be generated by the system, depending on the type of analyses being performed. You must provide an efficient laboratory ventilation system to remove toxic

products generated during instrument operation.

W1.3Warning: Explosive AtmosphereThis instrument is not designed for operation in an explosive atmosphere.

0993-5288 1-5


Safe handling of chemicals

Some chemicals used with the instrument may be hazardous or may become hazardous after completion of an analysis.

The responsible body1 must take the necessary precautions to ensure that the surrounding workplace is safe and that instrument operators are not exposed to hazardous levels of toxic substances (chemical or biological) as defined in the applicable national, state, and local health and safety regulations and laws.Venting for fumes and disposal of wastes must be in accordance with all national, state, and local health and safety regulations and laws.

Use, store, and dispose of chemicals in accordance with the manufacturer’s recommendations and the applicable national, state, and/or local regulations.

Wear appropriate eye protection at all times while handling chemicals. Depending on the types of chemicals you are handling, wear safety glasses with side shields, or goggles, or a full-face shield.

Wear suitable protective clothing, including gloves if necessary, resistant to the chemicals you are handling.

When preparing chemical solutions, always work in a fume hood that is suitable for the chemicals you are using.

Perform sample preparation away from the instrument to minimize corrosion and contamination.

Clean up spills immediately using the appropriate equipment and supplies, such as spill cleanup kits.

Do not put open containers of solvent near the instrument.

Store solvents in an approved cabinet (with the appropriate ventilation) away from the instrument.

1. Definitions from IEC 1010-1:Responsible body: ‘individual or group responsible for the use and maintenance of equipment, and for ensuring that operators are adequately trained.’Operator: ‘person operating equipment for its intended purpose.’

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Sodium tetrahydroborate

Sodium tetrahydroborate is used as a reductant in the mercury cold vapor technique and the hydride-generation technique. Sodium tetrahydroborate solutions are unstable and decompose, releasing hydrogen. Sodium tetrahydroborate also releases hydrogen when it comes into contact with acids.

Make sure that the work area has an adequate ventilation system to prevent the build-up of explosive air-hydrogen mixtures.

Use and store sodium tetrahydroborate according to the manufacturer’s recommendations.

Keep sodium tetrahydroborate solutions:– Out of direct sunlight.– Away from open flames.– In an area with an efficient ventilation system.

Protect sodium tetrahydroborate solutions from temperature variations.

Handle sodium tetrahydroborate solutions with care since they are corrosive.

Do not allow smoking in areas where sodium tetrahydroborate is used.

When you are using sodium tetrahydroborate as the reductant, hydrogen is formed when it comes into contact with the acidified measurement solution.– Do not loosen or remove any connections when the system is operating.– The maximum concentration of sodium tetrahydroborate that you should

use with the PerkinElmer MHS 15 system is 3% W/V (30 g/L).– At the end of the work session, purge the system with deionized water to

remove all traces of the reductant.

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Waste disposal

Disposing of reaction residues

Do not empty the reaction flask directly into the laboratory’s waste water system; there may be an excess of NaBH4 or SnCl2 in the flask.Collect the reaction residues in a suitable waste container. Store the waste container in a fume hood and make sure that the contents are sufficiently acidic so that NaBH4 residues react completely. Do not put a cap on the waste container.

Contents of waste containers

The materials that you collect in waste containers may include small amounts of the substances that were analyzed and other chemicals used in the analyses.If these materials are toxic, corrosive, or contain organics you may have to treat the collected effluent as hazardous waste. Refer to your local safety regulations for proper disposal procedures.

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Handling compressed gases

Note: The permanent installation of gas supplies is the responsibility of the user and should conform to local safety and building regulations.

Summary of gas hazards

Hazards associated with the different gases used in atomic absorption spectrometry are presented in the table below:

Contact the gas supplier for a safety data sheet containing detailed information on the potential hazards associated with the gas.

Identifying cylinders

Legibly mark cylinders to clearly identify the contents and status (full, empty, etc.). Use the chemical name or commercially accepted name for the gas.

Gas Suffocation Explosion

Spontaneous Decomposition or Combustion

Argon x – –Nitrogen x – –

Warning: Compressed GasesHigh pressure gas cylinders can be dangerous if mishandled or misused. Always handle gas cylinders with caution and observe your local regulations

for the safe handling of gas cylinders.

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Storing cylinders

Store cylinders in accordance with the applicable national, state, and/or local regulations and standards.

When gas cylinders are stored in confined areas, such as a storage room, make sure that ventilation is adequate to prevent toxic or explosive accumulations of gas. The storage room should be well ventilated and dry. This is particularly important in confined areas.

Do not store cylinders near elevators, gangways, or in locations where heavy moving objects may strike or fall against them.

Use and store cylinders away from exits and exit routes.

Locate gas cylinders away from heat sources, including heat lamps. Compressed gas cylinders should not be subjected to temperatures above 52 °C (125 °F).

Do not allow ignition sources in the storage area and keep cylinders away from readily ignitable substances such as gasoline or waste, or combustibles in bulk, including oil.

Store all gas cylinders only in a vertical position, with the valve cap in place, and fastened securely to an immovable bulkhead or a permanent wall.

If you are storing cylinders outdoors, store them above ground on a suitable floor where they are protected against temperature extremes (including the direct rays of the sun).

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Handling cylinders

Move cylinders with a suitable hand truck after making sure that the valve cap is securely in place and that the cylinder is properly fastened to the hand truck.

Use only approved regulators, tubing, and hose connectors. When you connect fittings, keep in mind that left-hand thread fittings are used for fuel gas connections (e.g., acetylene), whereas right-hand thread fittings are used for oxidant and support gas connections (e.g., nitrous oxide, air).

Arrange gas hoses where they will not be damaged or stepped on and where things will not be dropped on them.

Do not attempt to refill gas cylinders.

Check the condition of pipes, hoses, and connectors regularly, and replace any damaged parts.

Perform periodic gas leak tests at all joints and seals of the gas system by applying an approved gas leak detection solution.

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Safety practices for flame operation

Safety interlocks

PerkinElmer provides a number of safety interlocks on the burner system to monitor gas pressure and check for the proper setup of the burner head, nebulizer, and drain system. In addition a flame sensor checks that the flame is burning.

Do not attempt to defeat these interlocks; you may compromise your own, or someone else’s, safety.

Safe use of burner gases

The seepage of fuel gas or fuel gas mixture from the burner system, the drain system, the gas control system, or the gas connections constitutes a serious fire hazard.

Make sure that there are no breaks or leaks in any of these systems and that all the seals are correctly installed and in good condition.

Regularly check for leaks at joints and seals using an approved leak test solution.

When you perform any maintenance or installation procedures, follow the instructions in the guide exactly.

Do not attempt to service the gas control system yourself. A PerkinElmer service engineer, or similarly authorized and trained person, must perform the work.

When you shut down the instrument, for example at the end of the working day, shut all the gas lines at the cylinder or regulator valves. Bleed the lines between the regulator and instrument to atmosphere before switching off the ventilation system.

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Safe operation of the flame

Before you ignite the flame make sure that:– The laboratory fume ventilation system is operating;– The burner head is installed correctly;– The burner end cap is secured firmly;– The fuel and oxidant tubing fittings are properly connected;– The atomizer compartment door is closed.

Do not leave the flame unattended. Always make sure that there is a fire extinguisher near the instrument.

Never change the gas pressure or shut a gas valve while the flame is burning.

Do not allow the burner head slot to become blocked. This can cause a flashback of the flame.

Do not place open containers of flammable liquids and solvents near to the flame. Be especially careful with samples that contain highly volatile solvents.

Hazards with flame operation

High temperatures

The flame can generate temperatures of up to 2800 °C.

To avoid serious burns, never touch the quartz tube atomizer (QTA), QTA mount, or burner head until they have cooled to room temperature.

UV radiation

The flame emits ultraviolet radiation.

Keep the atomizer compartment door closed when the flame is burning and never directly view the flame unless you are wearing UV-absorbing glasses.

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Safety practices for mercury/hydride systems

FIAS-Cells – To all users who have an MHS 15 in addition to FIAS

Never use the FIAS-cell for the MHS 15.

The smaller diameter of the FIAS-cell can cause an increase in back pressure. This could force the acidic reaction mixture back into the sodium tetrahydroborate bottle where large quantities of hydrogen would be produced.

Safety checks

Before you start an analysis, make sure that:– The laboratory fume ventilation system is operating;– The tubing in the system is not constricted since this could lead to a

pressure build-up in the system;

If you are using a flame to heat the QTA, refer to the information under ‘Safety practices for flame operation’ on page 1-12 before you ignite the flame.

Hazards with mercury/hydride systems

Toxic products

Toxic metal vapors, hydrogen, etc., can be generated by the system, depending on the type of analyses being performed.

You must provide an efficient laboratory ventilation system to remove toxic products generated during instrument operation.

High temperatures

The QTA used for the hydride-generation technique can reach temperatures of up to 1000 C.

Do not touch any part of the QTA mount or the QTA until they have cooled to room temperature.

1-14 0993-5288


Hazardous chemicals

Some of the chemicals required for analyses are corrosive and/or toxic. Refer to the information under ‘Safe handling of chemicals’ on page 1-6 and

to the specific warnings in the documentation provided with the system before you start an analysis.

Operational precautions

The MHS 15 mercury/hydride system is characterized by simplicity of operation. Nevertheless you should realize that during the determination a chemical reaction takes place with the liberation of hydrogen when you are using NaBH4 as the reductant. Since hydrogen can form flammable mixtures with air, you must take the following precautions to prevent the buildup of air-hydrogen mixtures. Carefully observe the precautions listed under ‘Sodium tetrahydroborate’ on

page 1-7. Do not fill the reductant bottle more than three-quarters full. Do not position the reactor assembly such that the reductant bottle can be

subjected to heat radiation from the flame. Do not overfill the reaction flask. The maximum prepared measurement

solution volume is 50 mL. Once the reaction has been started, do not remove the reaction flask from the

reactor assembly and then reconnect it. Air entrained in the flask may lead to the formation of a potentially flammable air-hydrogen mixture.If you have to remove the reaction flask before the reaction is complete (e.g. due to excessive foam development), place the flask in a fume hood until the liberation of hydrogen has ceased. Repeat the determination on a fresh sample.

Do not empty the reaction flask directly into the laboratory’s waste water system; there may be an excess of NaBH4 in the flask.

Make sure that the sample transfer tube is not restricted in any way and that the flashback arrestor is not blocked.

Never depress the plunger when a reaction flask or other vessel is not placed underneath the immersion tube.

Do not operate the system with the graphite cooling rings removed from the ends of the QTA.

At the end of the working day, purge the reductant transfer system with deionized water to remove any reductant residues.

0993-5288 1-15


References for laboratory safety practice

Bretherik, L., Bretherik’s Handbook of Reactive Chemical Hazards, 4th ed., Butterworth & Co. Ltd., London, UK, 1990.

Safe Practices in Chemical Laboratories,Royal Society of Chemistry, London, UK, 1989.

Hazards in the Chemical Laboratory, 5th edition, Luxon, S.G., ed., Royal Society of Chemistry, London, UK, 1992.

CRC Handbook of Laboratory Safety, 3rd edition, Furr, K., ed., The Chemical Rubber Co. Press, Florida, USA, 1990.

Prudent Practices for Handling Hazardous Chemicals in Laboratories, National Research Council, National Academic Press, Washington D.C., USA, 1981.

Sax’s Dangerous Properties of Industrial Materials, 9th edition, Sax, N.I. and Lewis, R.J., eds.,Wiley, New York, USA, 1998.

Pohanish, R.P. and Greene, S.A., Hazardous Materials Handbook,Wiley, New York, USA, 1996.

Compressed Gas Association, Inc., Arlington, VA 22202, USA, various publications.

Data Sheets provided by chemical manufacturers, e.g.:– USA, Material Safety Data Sheets (MSDS),– FRG, DIN-Sicherheitsblätter,– UK, Hazard Data Sheets.

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Regulatory information

This instrument has been designed to comply with a wide variety of international standards governing the safety of laboratory equipment. In routine use, the instrument poses virtually no risk to you. If you take some simple, common-sense precautions, you can maintain the continued safe operation of the instrument.

0993-5288 1-17


1-18 0993-5288

Setting up the system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Positioning the MHS 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Preparing the system for analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4Aligning the QTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6Selecting operating mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Performing a measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10Methods development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

MHS 15:Analyzing Samples 2

2MHS 15: Analyzing SamplesMarker for header

Contents page

0993-5288 2-1

MHS 15: Analyzing Samples

2-2 0993-5288


Setting up the system

Positioning the MHS 15 1. Place the MHS 15 reactor assembly adjacent to the spectrometer’s atomizer

compartment. A small table in front of the spectrometer is ideal.

2. Remove the QTA from the holder at the rear of the reactor assembly and place it in the QTA bracket on the burner.Position the QTA so that the side arm rests in the locating notch in the QTA bracket. Note: Make sure that the transfer tube runs in a smooth loop from the reactor assembly and that it cannot be pinched or kinked. A restriction in the transfer tube can lead to a pressure buildup in the system.

Figure 2-1. QTA mounted on the burner

Note: When you position the MHS 15 in front of the spectrometer, make sure that the reductant bottle is not exposed to heat radiation from the flame.

Hinged QTA bracket(shown in down position)

Burner head

Burner spraychamber

QTA

Transfer tubefrom reactor assembly

(nebulizer not shown)

0993-5288 2-3


Preparing the system for analyses

1. Read the safety information at the front of this guide and in the spectrometer’s guide before you operate the system.

2. Switch on the fume ventilation system for the work area.

3. Install the proper radiation source for the element to be determined.

4. Switch on the spectrometer, following the routine described in the spectrometer’s guide.

5. Select the atomization technique (refer to the spectrometer’s guide).For the MHS 15, select the Flame technique.

6. Set up a method on the spectrometer (refer to the spectrometer’s guide or the Online Help in AA WinLab).1. Select Peak Height for Signal Measurement.2. Select a Read Time of sufficient length (more information: page 2-13).3. Do not select a Read Delay.

7. Align the radiation source for maximum energy.

8. Perform fine alignment of the QTA, if required (procedure: page 2-7).

9. If you require a flame to heat the QTA, turn on the burner gases and adjust the outlet gauge pressures to the recommended values (refer to the spectrometer’s guide).You do not require a flame to heat the QTA for mercury determinations.

10. With the QTA tilted out of the radiation beam, ignite the air-acetylene flame.To prevent soot formation on the QTA, use a lean, oxidizing flame.

11. Tilt the QTA into the radiation beam and allow 10 to 15 minutes for stabilization in the flame before you start measurements.

12. Prepare the required reductant solution (refer to the Recommended Conditions for the analyte element).

13. Fill the reductant bottle three-quarters full with the reductant solution.Do not overfill the bottle.Screw the reductant bottle finger-tight into the fitting on the reactor assembly.

14. Select the operating mode for the reductant you are using, if required (procedure: page 2-8).

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15. Turn on the inert gas supply to the reactor assembly and set the outlet gauge pressure to 250 kPa (see Table 7-1 on page 7-6).

Note: Inert gas flows continuously when the supply is turned on. To conserve gas, turn off the supply during longer pauses in operation.Since the pressure of the inert gas to the MHS 15 has a slight influence on the flow rate of the gas through the system, always set the pressure consistently to 250 kPa.

Figure 2-2. Reactor assembly with reductant bottle

Inert gas

Reductant bottle

Fitting forreductant bottle

0993-5288 2-5


Aligning the QTA

Before you perform analyses, you must align the QTA in the spectrometer’s sample beam to make sure that the radiation passes through the QTA and does not impinge on the walls.

1. Coarse alignment

You should perform coarse alignment at the first installation of the QTA burner mount and every time that you have removed the burner head from the burner.

1. Tilt the QTA bracket to the up position, out of the radiation beam.

2. Install a suitable radiation source in the spectrometer that emits a beam of visible light, such as a copper hollow cathode lamp.

3. Switch on the spectrometer, following the routine described in the spectrometer’s guide.Do not ignite the flame.

4. Align the radiation source for maximum energy.

5. Tilt the QTA bracket to the down position so that the QTA is in the radiation beam.

6. Hold a piece of white paper at the radiation exit end of the QTA and visually inspect the light spot.

7. If necessary, make incremental adjustments to the burner’s adjustment controls so that the radiation beam passes through the QTA without impinging on the walls.

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2. Fine alignment

Perform fine alignment before the start of every analysis series.

1. Tilt the QTA bracket to the up position, out of the radiation beam.

2. Install the proper radiation source for the element to be determined.

3. Set up the spectrometer for the determination as described in the spectrometer’s guide.Do not ignite the flame.

4. Tilt the QTA bracket to the down position so that the QTA is in the radiation beam.

5. Select the correct mode on the spectrometer for performing optimization procedures (normally Continuous mode on most instruments).Do not select background correction.

6. If necessary, make incremental adjustments to the burner’s adjustment controls to obtain the lowest possible absorbance reading.

This completes the fine alignment procedure.

W3.1Warning: UV Radiation – Risk of Eye DamageThe lamps may emit UV radiation which can damage your eyes. Do not gaze into a lighted lamp. Always wear UV-absorbing safety glasses when looking at the radiation from

the lamps.

0993-5288 2-7


Selecting operating mode

Figure 2-3. Reductant changeover valve

If the reductant changeover valve is not set to the reductant you intend to use, change the position of the valve as follows:

1. Slacken, but do not remove, the wing nut.

2. Lift up the valve cover to release the locking pin (on the underside).

3. Turn the valve cover until the black arrow is opposite the required reductant.

4. Lower the valve cover, making sure that the locking pin locates in the hole.

5. Tighten the wing nut finger-tight.

Reductant changeover valve

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Figure 2-4. Reductant changeover valve set to NaBH4

Note: If you determine mercury using tin(II) chloride as the reductant, the apparatus will be contaminated with tin. If you subsequently determine tin in the same apparatus using sodium tetrahydroborate as the reductant, the tin contamination will interfere in the determination. Since tin is a hydride-forming element, the tin contamination may also interfere in the determination of other hydride-forming elements.If you change regularly between SnCl2 and NaBH4, we strongly recommend that you purchase a second MHS 15 and reserve it solely for use with SnCl2. Likewise you should reserve a set of reaction flasks, an immersion tube, and a reductant bottle solely for use with SnCl2.A set of adhesive labels is provided with the MHS 15 so that you can mark the reductant being used.

Valve cover

Wing nut

0993-5288 2-9


Performing a measurement

Note: If you are going to analyze a sample of unknown composition, perform a preliminary trial first to check whether there is excessive foaming or precipitation (more information: page 9-9).

1. Read and make note of the operational precautions at the front of this guide before you operate the system (see page 1-15).

2. Set up the system as described under ‘Preparing the system for analyses’ on page 2-4.

3. Prepare calibration and test sample solutions as required.

4. Dispense 10 mL (or the required volume) of dilute acid into the reaction flask using a measuring cylinder.

5. Dispense an accurately measured volume of a test solution (a blank solution, a calibration solution, or a test sample solution) into the reaction flask using a suitable pipet.

6. Attach the reaction flask to the reactor assembly: 1. Insert the reaction flask into the socket.2. Turn the reaction flask so that the lugs are gripped in the bayonet lock.

7. Wait for the pre-reaction purge time (more information: page 2-12).Note: You do not need to wait if you are using SnCl2 as reductant.

8. Start the Read function on the spectrometer (refer to the spectrometer’s guide or the Online Help in AA WinLab).

9. Wait for approximately 5 seconds for the spectrometer to perform BOC.

Warning: Corrosive Chemicals – Risk of BurnsSome of the chemicals used with the instrument are hazardous (acids, reductant solutions, etc.). When using hazardous chemicals, always wear suitable protective clothing

including eye protection, and observe the manufacturer’s instructions and your local safety regulations.

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Figure 2-5. Attaching the reaction flask

10. Depress and hold the plunger for the predetermined reaction time (more information: page 2-13 ).Note: Release the plunger immediately if foam is transported into the flashback arrestor or the QTA.

11. Then release the plunger and wait for the post-reaction purge time (more information: page 2-13 ).

12. Remove the reaction flask from the reactor assembly and empty the contents into a waste container.

13. Holding the reaction flask under the immersion tube, use a wash bottle to rinse the immersion tube with dilute acid.

14. Rinse the inside of the reaction flask with dilute acid and empty the contents into a waste container.

15. Follow the above procedure to measure all other test solutions.

Reaction flask socket

Lugs

Reaction flask

with bayonet lock

Plunger

0993-5288 2-11


Methods development

To establish the optimum periods for the pre- and post-reaction purge times, the reaction time, and also the Read Time on the spectrometer, you must perform preliminary measurements.

Pre-reaction purge time

As explained on page 9-4, you must purge the system free of air before starting a measurement when you are using NaBH4 as reductant. The pre-reaction purge time for each element quoted in the Recommended Conditions is generally adequate. However, for arsenic and selenium you should determine the pre-reaction purge time experimentally for your system, since radiation absorption by air in the QTA can interfere in the determination of these elements.


2. Set up a method on the spectrometer for the element you wish to determine (refer to the spectrometer’s guide or the Online Help in AA WinLab).

3. Display the Continuous Graphics window.You will obtain a continuous absorbance reading since air in the QTA absorbs radiation.

4. Connect an empty reaction flask to the reactor assembly.

5. Watch the continuous graphics display.As air is purged from the system by the inert gas, the absorbance plot falls toward the baseline.

6. Wait until the plot levels out on the baseline and then note the time taken.This is the pre-reaction purge time.

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Reaction time, post-reaction purge time, and read time

Determine the reaction time and post-reaction purge time by measuring a suitable calibration solution of the analyte element, as described below:


2. Set up a method on the spectrometer for the element you wish to determine (refer to the spectrometer’s guide or the Online Help in AA WinLab).

3. Display the Continuous Graphics window.

4. Dispense 10 mL dilute acid into the reaction flask using a measuring cylinder.

5. Dispense an accurately measured volume of a calibration solution into the reaction flask using a suitable pipet.

6. Attach the reaction flask to the reactor assembly.

7. Wait for the pre-reaction purge time.

8. Depress and hold the plunger.

9. Watch the continuous graphics display.1. An analyte absorbance signal will be generated. 2. Keep the plunger depressed until peak maximum has clearly been

exceeded and the peak starts to fall. 3. Then release the plunger.4. Note the time taken until you released the plunger.

This is the reaction time.

10. Continue to watch the continuous graphics display.1. As the analyte element is purged from the system, the absorbance plot

falls toward the baseline.2. Wait until the plot levels out on the baseline and then note the time taken

from when you released the plunger.This is the post-reaction purge time.

11. The Read Time you select in the spectrometer method should be 5–10 s longer than the reaction time.

0993-5288 2-13


2-14 0993-5288

The recommended analytical conditions for the determination of individual elements are listed alphabetically by element symbol in this section.Safe handling of chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3Recommended conditions for arsenic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5Recommended conditions for bismuth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7Recommended conditions for mercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9Recommended conditions for mercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11Recommended conditions for antimony . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13Recommended conditions for selenium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15Recommended conditions for tin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17Recommended conditions for tellurium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19

MHS 15:Recommended Analytical Conditions 3

3MHS 15: Recommended Analytical ConditionsMarker for header

Contents page

0993-5288 3-1

MHS 15: Recommended Analytical Conditions

3-2 0993-5288


Safe handling of chemicals

Some chemicals used with the instrument may be hazardous or may become hazardous after completion of an analysis. Use, store, and dispose of chemicals in accordance with the manufacturer’s

recommendations and the applicable national, state, and/or local regulations. Wear appropriate eye protection at all times while handling chemicals.

Depending on the types of chemicals you are handling, wear safety glasses with side shields, or goggles, or a full-face shield.

Wear suitable protective clothing, including gloves if necessary, resistant to the chemicals you are handling.

When preparing chemical solutions, always work in a fume hood that is suitable for the chemicals you are using.

Perform sample preparation away from the instrument to minimize corrosion and contamination.

Clean up spills immediately using the appropriate equipment and supplies, such as spill cleanup kits.

Sodium tetrahydroborate

Sodium tetrahydroborate is used as a reductant in the mercury cold vapor technique and the hydride-generation technique. Sodium tetrahydroborate solutions are unstable and decompose, releasing hydrogen. Sodium tetrahydroborate also releases hydrogen when it comes into contact with acids. Make sure that the work area has an adequate ventilation system to prevent

the build-up of explosive air-hydrogen mixtures. Use and store sodium tetrahydroborate according to the manufacturer’s

recommendations. Keep sodium tetrahydroborate solutions:

– Out of direct sunlight.– Away from open flames.– In an area with an efficient ventilation system.

Protect sodium tetrahydroborate solutions from temperature variations. Handle sodium tetrahydroborate solutions with care since they are corrosive. Do not allow smoking in areas where sodium tetrahydroborate is used.

0993-5288 3-3


3-4 0993-5288


Recommended conditions for arsenic Reagents 0.15 mol/L (]=1.5% V/V)

hydrochloric acid:0.25 mol/L (] 1% W/V) NaOH solution:

0.8 mol/L (] 3% W/V) NaBH4 solution:

Carefully add 15 mL conc. HCl to deionized water and make up to 1 L.Carefully dissolve 10 g sodium hydroxide flakes in deionized water and make up to 1 L.Dissolve 3 g sodium tetrahydroborate in 1% NaOH solution and make up to 100 mL with 1% NaOH solution.

Stock solution The stock solution contains 1000 mg/L As.The use of commercially-available concentrated calibration solutions for AAS is recommended.Warning: Arsenic solutions are toxic.

Calibration solutionAliquots for calibration:Corresponding to:Diluent:Calibration volume:

1 mg As/L (in 1.5% HCl)10, 25, 50 µL10, 25, 50 ng As1.5% (V/V) hydrochloric acid10 mL(Refer to ‘Calibration techniques’ on page 9-6 for more information)

Reductant solution 3% NaBH4 in 1% NaOH solution.

Oxidation state The hydride is generated much more slowly from As(V) than from As(III). To prevent interferences, As(V) must be prereduced to As(III) prior to the determination.Prereduction can be performed with KI in semiconcentrated (5 mol/L) HCl solution or, preferably, with L-cysteine 1,2.

References: 1. Welz, B.; M. Šucmanová, Analyst (London) 118/11, 1417–1423 (1993)2. Welz, B.; M. Šucmanová, Analyst (London) 118/11, 1425–1432 (1993)

As

0993-5288 3-5


Recommended conditions for arsenic (cont.)

Prereduction 1. KI solution: Dissolve 3 g KI and 5 g L(+)-ascorbic acid in 100 mL water. Prepare fresh daily. Add 1 mL of the KI solution per 10 mL of the sample solution in 5 mol/L HCl and stand for 30 min.–or–

2. L-cysteine solution: Dissolve 5 g L-cysteine in 100 mL 0.5 mol/L HCl. This solution is stable for at least a month. Add 2 mL of the L-cysteine solution per 10 mL of the sample solution and stand for 30 min.

Analytical wavelength 193.7 nm

Slit width and height 0.7 nm Low

Radiation source Electrodeless discharge lamp for As.

QTA heating Heat the QTA in a lean, blue air-acetylene flame.

Prepared measurement volume

10 mL minimum to 50 mL maximum.

Pre-reaction purge time approx. 50 s

Post-reaction purge time approx. 40 s

Characteristic mass 0.95 ng As for 1% absorption (A=0.0044).

Characteristic concentration

0.095 µg/L / 1% absorption for 10 mL calibration volume.

Characteristic concentration check

50 µL of the 1000 mg/L As stock solution (50 ng) give an absorbance of approx. A=0.2.

Alternate analytical wavelengths

Wavelengthnm

Slit widthnm

Sensitivity relative to main analytical wavelength

189.0197.2

0.70.7

0.82.0

Notes Condition the QTA in cold hydrofluoric acid if there is a decrease in sensitivity (and other causes are excluded) (procedure: page 4-8).

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Recommended conditions for bismuth Reagents 0.15 mol/L (]=1.5% V/V)




Stock solution The stock solution contains 1000 mg/L Bi.The use of commercially-available concentrated calibration solutions for AAS is recommended.


1 mg Bi/L (in 1.5% HCl)25, 50, 100 µL25, 50, 100 ng Bi1.5% (V/V) hydrochloric acid10 mL(Refer to ‘Calibration techniques’ on page 9-6 for more information)


Oxidation state The rate of hydride-generation is different for Bi(V) and Bi(III). To prevent interferences, Bi(V) must be prereduced to Bi(III) prior to the determination.Bi(V) is reduced immediately to Bi(III) by the addition of conc. HCl.

Bi

0993-5288 3-7


Recommended conditions for bismuth (cont.)



Radiation source Electrodeless discharge lamp for Bi.






Characteristic mass 1.46 ng Bi for 1% absorption (A=0.0044).




100 µL of the 1000 mg/L Bi stock solution (100 ng) give an absorbance of approx. A=0.3.


Wavelengthnm

Slit widthnm


222.8306.8206.2227.7

0.20.70.20.2

2.43.78.6

14.0

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Recommended conditions for mercury Using sodium tetrahydroborate (NaBH4) as reductant

Reagents 0.15 mol/L (] 1.5% V/V) hydrochloric acid:0.22 mol/L (] 1.5% V/V) nitric acid:5% (W/V) KMnO4 solution:

0.25 mol/L (] 1% W/V) NaOH solution:


Carefully add 15 mL conc. HCl to deionized water and make up to 1 L.Carefully add 15 mL conc. HNO3 to deionized water and make up to 1 L.Dissolve 5 g potassium permanganate in deionized water and make up to 100 mL.Carefully dissolve 10 g sodium hydroxide flakes in deionized water and make up to 1 L.Dissolve 3 g sodium tetrahydroborate in 1% NaOH solution and make up to 100 mL with 1% NaOH solution.

Stock solution The stock solution contains 1000 mg/L Hg.The use of commercially-available concentrated calibration solutions for AAS is recommended.Warning: Mercury solutions are toxic.

Calibration solution

Aliquots for calibration:Corresponding to:Diluent:Calibration volume:

1 mg Hg/L (in 1.5% HNO3, stabilized by the addition of a few drops of 5% KMnO4 solution)100, 200, 500 µL100, 200, 500 ng Hg1.5% (V/V) nitric acid or 1.5% (V/V) hydrochloric acid10 mL(Refer to ‘Calibration techniques’ on page 9-6 for more information)


Hg

0993-5288 3-9


Recommended conditions for mercury using NaBH4 (cont.)



Radiation source Electrodeless discharge lamp or hollow cathode lamp for Hg.

QTA heating No flame required.If condensation in the QTA is a problem, heat the QTA gently by mounting an infrared lamp above it.





Characteristic mass 4.68 ng Hg for 1% absorption (A=0.0044).




250 µL of the 1000 mg/L Hg stock solution (250 ng) give an absorbance of approx. A=0.2.

Notes Stabilize stock and calibration solutions by adding KMnO4 or KI solution. (Refer to ‘Reagents and calibration solutions’ on page 9-8 for more information.)Stabilize all solutions in the reaction flask by adding 1 drop of 5% (W/V) KMnO4 solution before starting the determination.

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Recommended conditions for mercury Using tin(II) chloride (SnCl2) as reductant

Reagents 0.15 mol/L (] 1.5% V/V) hydrochloric acid:1 mol/L (] 10% V/V) hydrochloric acid:0.22 mol/L (] 1.5% V/V) nitric acid:5% (W/V) KMnO4 solution:

5% (W/V) SnCl2 solution:

Carefully add 15 mL conc. HCl to deionized water and make up to 1 L.Carefully add 100 mL conc. HCl to deionized water and make up to 1 L.Carefully add 15 mL conc. HNO3 to deionized water and make up to 1 L.Dissolve 5 g potassium permanganate in deionized water and make up to 100 mL.Dissolve 50 g tin(II) chloride dihydrate (SnCl2 2H2O) in 10% HCl solution and make up to 1 L with 10% HCl solution.

Stock solution The stock solution contains 1000 mg/L Hg.The use of commercially-available concentrated calibration solutions for AAS is recommended.Warning: Mercury solutions are toxic.

Calibration solution

Aliquots for calibration:Corresponding to:Diluent:Calibration volume:

1 mg Hg/L (in 1.5% HNO3, stabilized by the addition of a few drops of 5% KMnO4 solution)100, 200, 500 µL100, 200, 500 ng Hg1.5% (V/V) nitric acid or 1.5% (V/V) hydrochloric acid10 mL(Refer to ‘Calibration techniques’ on page 9-6 for more information)

Reductant solution 5% SnCl2 2H2O in 10% HCl solution.

Hg

0993-5288 3-11


Recommended conditions for mercury using SnCl2 (cont.)



Radiation source Electrodeless discharge lamp or hollow cathode lamp for Hg.

QTA heating No flame required. If condensation in the QTA is a problem, heat the QTA gently by mounting an infrared lamp above it.





Characteristic mass 4.68 ng Hg for 1% absorption (A=0.0044).




250 µL of the 1000 mg/L Hg stock solution (250 ng) give an absorbance of approx. A=0.2.

Notes Stabilize stock and calibration solutions by adding KMnO4 solution.Do not use KI solution since iodide interferes in the release of mercury.(Refer to ‘Reagents and calibration solutions’ on page 9-8 for more information.)Stabilize all solutions in the reaction flask by adding 1 drop of 5% (W/V) KMnO4 solution before starting the determination.

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Recommended conditions for antimony Reagents 0.3 mol/L (] 3% V/V)

hydrochloric acid:0.15 mol/L (] 1.5% V/V) hydrochloric acid:0.25 mol/L (] 1% W/V) NaOH solution:


Carefully add 30 mL conc. HCl to deionized water and make up to 1 L.Carefully add 15 mL conc. HCl to deionized water and make up to 1 L.Carefully dissolve 10 g sodium hydroxide flakes in deionized water and make up to 1 L.Dissolve 3 g sodium tetrahydroborate in 1% NaOH solution and make up to 100 mL with 1% NaOH solution.

Stock solution The stock solution contains 1000 mg/L Sb.The use of commercially-available concentrated calibration solutions for AAS is recommended.Warning: Antimony solutions are toxic.


1 mg Sb/L (in 1.5% HCl)50, 100, 200 µL50, 100, 200 ng Sb3% (V/V) hydrochloric acid10 mL(Refer to ‘Calibration techniques’ on page 9-6 for more information)


Oxidation state The hydride is generated much more slowly from Sb(V) than from Sb(III). To prevent interferences, Sb(V) must be prereduced to Sb(III) prior to the determination.Prereduction can be performed with KI in semiconcentrated (5 mol/L) HCl solution or, preferably, with L-cysteine 1,2.

References: 1. Welz, B.; M. Šucmanová, Analyst (London) 118/11, 1417–1423 (1993)2. Welz, B.; M. Šucmanová, Analyst (London) 118/11, 1425–1432 (1993)

Sb

0993-5288 3-13


Recommended conditions for antimony (cont.)

Prereduction 1. KI solution: Dissolve 3 g KI and 5 g L(+)-ascorbic acid in 100 mL water. Prepare fresh daily. Add 1 mL of the KI solution per 10 mL of the sample solution in 5 mol/L HCl.–or–

2. L-cysteine solution: Dissolve 5 g L-cysteine in 100 mL 0.5 mol/L HCl. This solution is stable for at least a month. Add 2 mL of the L-cysteine solution per 10 mL of the sample solution. Reduction is spontaneous.



Radiation source Electrodeless discharge lamp for Sb.






Characteristic mass 2.05 ng Sb for 1% absorption (A=0.0044).




100 µL of the 1000 mg/L Sb stock solution (100 ng) give an absorbance of approx. A=0.2.


Wavelengthnm

Slit widthnm


206.8231.2

0.20.2

1.52.1

3-14 0993-5288


Recommended conditions for selenium Reagents 0.15 mol/L (] 1.5% V/V)




Stock solution The stock solution contains 1000 mg/L Se.The use of commercially-available concentrated calibration solutions for AAS is recommended.Warning: Selenium solutions are toxic.


1 mg Se/L (in 1.5% HCl)20, 50, 100 µL20, 50, 100 ng Se1.5% (V/V) hydrochloric acid10 mL(Refer to ‘Calibration techniques’ on page 9-6 for more information)


Oxidation state Se(VI) does not generate a measurable signal. To prevent interferences, Se(VI) must be prereduced to Se(IV) prior to the determination. Prereduction can be performed by heating with 5–6 mol/L HCl for 15–30 minutes under reflux 3,4.

References: 3. Bye, R.; W. Lund, Fresenius Z. Anal. Chem.332/3 , 242–244 (1988)4. Pettersson, J.; Å. Olin, Talanta 38/4 , 413–417 (1991)

Se

0993-5288 3-15


Recommended conditions for selenium (cont.)



Radiation source Electrodeless discharge lamp for Se.






Characteristic mass 2.2 ng Se for 1% absorption (A=0.0044).




100 µL of the 1000 mg/L Se stock solution (100 ng) give an absorbance of approx. A=0.2.


Wavelengthnm

Slit widthnm


204.0206.3

0.70.7

3.011.0

Notes Potassium iodide (KI) reduces selenium to the element, which does not react to form the hydride. Systems that have been contaminated with high concentrations of KI must be thoroughly cleaned before they can be used for the determination of selenium.

3-16 0993-5288


Recommended conditions for tin Reagents saturated boric acid solution:

0.05 mol/L (] 0.5% V/V) hydrochloric acid:0.15 mol/L (] 1.5% V/V) hydrochloric acid:0.25 mol/L (] 1% W/V) NaOH solution:


approx. 50 g/L H3BO4 in 0.5% hydrochloric acid.Carefully add 5 mL conc. HCl to deionized water and make up to 1 L.Carefully add 15 mL conc. HCl to deionized water and make up to 1 L.Carefully dissolve 10 g sodium hydroxide flakes in deionized water and make up to 1 L.Dissolve 3 g sodium tetrahydroborate in 1% NaOH solution and make up to 100 mL with 1% NaOH solution.

Stock solution The stock solution contains 1000 mg/L Sn.The use of commercially-available concentrated calibration solutions for AAS is recommended.


1 mg Sn/L (in 1.5% HCl)20, 50, 100 µL20, 50, 100 ng Snsaturated boric acid solution25 mL(Refer to ‘Calibration techniques’ on page 9-6 for more information)


Sn

0993-5288 3-17


Recommended conditions for tin (cont.)



Radiation source Electrodeless discharge lamp for Sn.






Characteristic mass 2.2 ng Sn for 1% absorption (A=0.0044).




100 µL of the 1000 mg/L Sn stock solution (100 ng) give an absorbance of approx. A=0.2.


Wavelengthnm

Slit widthnm


224.6235.5270.7303.4254.7219.9300.9233.5

0.20.70.70.20.70.20.70.7

1.81.62.93.85.45.76.96.9

Notes Memory signals are occasionally encountered during the determination of tin.Condition the QTA in cold hydrofluoric acid if there is a decrease in sensitivity (and other causes are excluded) (procedure: page 4-8).

3-18 0993-5288


Recommended conditions for tellurium Reagents 0.15 mol/L (] 1.5% V/V)

hydrochloric acid:0.3 mol/L (] 3% V/V) hydrochloric acid:0.44 mol/L (] 3% V/V) nitric acid:0.25 mol/L (] 1% W/V) NaOH solution:


Carefully add 15 mL conc. HCl to deionized water and make up to 1 L.Carefully add 30 mL conc. HCl to deionized water and make up to 1 L.Carefully add 30 mL conc. HNO3 to deionized water and make up to 1 L.Carefully dissolve 10 g sodium hydroxide flakes in deionized water and make up to 1 L.Dissolve 3 g sodium tetrahydroborate in 1% NaOH solution and make up to 100 mL with 1% NaOH solution.

Stock solution The stock solution contains 1000 mg/L Te.The use of commercially-available concentrated calibration solutions for AAS is recommended.Warning: Tellurium solutions are very toxic.


1 mg Te/L (in 1.5% HCl)20, 50, 100 µL20, 50, 100 ng Te3% (V/V) hydrochloric acid + 3% (V/V) nitric acid10 mL(Refer to ‘Calibration techniques’ on page 9-6 for more information)


Oxidation state Te(VI) does not generate a measurable signal. To prevent interferences, Te(VI) must be prereduced to Te(IV) prior to the determination.Prereduction can be performed by heating briefly with 5–6 mol/L HCl.

Te

0993-5288 3-19


Recommended conditions for tellurium (cont.)



Radiation source Electrodeless discharge lamp for Te.






Characteristic mass 1.1 ng Te for 1% absorption (A=0.0044).




40 µL of the 1000 mg/L Te stock solution (40 ng) give an absorbance of approx. A=0.15.

Notes Condition the QTA in cold hydrofluoric acid if there is a decrease in sensitivity (and other causes are excluded) (procedure: page 4-8).

3-20 0993-5288

PerkinElmer Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3Routine maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

Maintaining the flashback arrestor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6QTA maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7Replacing worn parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

MHS 15: Maintenance 44MHS 15: Maintenance

Marker for header

Contents page

0993-5288 4-1

MHS 15: Maintenance

4-2 0993-5288

MHS 15: Maintenance

PerkinElmer Service

If the instrument does not function correctly…

Contact your local PerkinElmer office.

You should only perform the maintenance procedures described in this guide.For any other maintenance or service contact your local PerkinElmer office to arrange for a service engineer to visit.In particular you must only allow a PerkinElmer service engineer or PerkinElmer trained person to perform any work on the pneumatic components inside the instrument.

Before the service engineer arrives:

1. Make sure that the instrument and the work area are clean.

2. Make certain that there are no corrosive solutions present in any of the tubes.

W1.2Warning: Unauthorized Adjustments and ServicingOnly a PerkinElmer service engineer or similarly trained and authorized person should be permitted to service the instrument. Do not attempt to make adjustments, replacements, repairs, or modifications

to this instrument except as described in the documentation supplied with the instrument.

0993-5288 4-3

MHS 15: Maintenance

Routine maintenance

The MHS 15 is a precision instrument constructed from high quality components. To maintain the high level of performance, you must treat the instrument with due care.

Maintenance checklist

External surfaces Regularly wipe over the surfaces with a lint-free cloth moistened with a dilute solution of laboratory detergent.The surfaces are resistant to dilute acids and alkalis, and to a lesser extent to strong acids and alkalis and organic solvents. Immediately clean all spilled materials from the affected area. Wear protective gloves if the materials are toxic or corrosive.Remove the drip tray and wash it in detergent solution as required.

Reaction flask During routine operation, rinse the reaction flask with dilute acid at regular intervals.For mercury use 1.5% to 3% (V/V) nitric acid.For hydride-forming elements use 1.5% to 3% (V/V) hydrochloric acid.

Immersion tube During routine operation, rinse the outside of the immersion tube with dilute acid after every measurement, and periodically remove it and rinse it with dilute acid.

Reductant bottle At the end of the working day, unscrew the reductant bottle from the reactor assembly and place it in a fume hood.Do not stopper a bottle containing NaBH4.

Reductant transport system

At the end of every working day, purge the reductant transport system well with deionized water (procedure: page 4-5).

Flashback arrestor

Check the baffle in the flashback arrestor regularly to make sure that it has not become blocked (procedure: page 4-6).

Transfer tube Check the condition of the transfer tube regularly. If it shows signs of deterioration, or has become seriously contaminated, replace it (more information: page 4-10).

4-4 0993-5288

MHS 15: Maintenance

Reductant transport system

At the end of every working day, purge (flush) the reductant transport system well with deionized water.

1. Unscrew the reductant bottle from the reactor assembly and place it in a fume hood. Do not stopper the bottle if it contains NaBH4.

2. Screw a plastic bottle containing deionized water into the fitting in the reactor assembly.

3. Place a beaker under the immersion tube.

4. Press and hold down the plunger for some time so that the reductant transport tubes are well purged with deionized water.

5. Empty the beaker and unscrew the plastic bottle.

6. Shut down the inert gas supply at source.

Disposing of reaction residues

Do not empty the reaction flask directly into the laboratory’s waste water system; there may be an excess of NaBH4 or SnCl2 in the flask.Collect the reaction residues in a suitable waste container. Store the waste container in a fume hood and make sure that the contents are sufficiently acidic so that NaBH4 residues react completely. Do not put a cap on the waste container.

Contents of waste containers

The materials that you collect in waste containers include small amounts of the substances that were analyzed and other chemicals used in the analyses.If these materials are toxic, corrosive, or contain organics you may have to treat the collected effluent as hazardous waste. Refer to your local safety regulations for proper disposal procedures.

0993-5288 4-5

MHS 15: Maintenance

Maintaining the flashback arrestor

Check the flashback arrestor regularly to see that the internal baffle has not become blocked. Always clean the baffle if any solution is transported into it.

Check and clean the flashback arrestor as follows:

1. Shut down the inert gas supply at source.

2. Disconnect the transfer tube from the QTA.

3. Screw the flashback arrestor apart and take out the perforated baffle.

4. Check the holes in the baffle for blockage.Soak the baffle in dilute hydrochloric acid, if required.Rinse the baffle with deionized water and dry before reassembly.

5. Place the baffle back into the arrestor, screw the arrestor back together, and reconnect the transfer tube to the QTA.

Warning: Pressure buildup in the systemBlockage of any of the holes in the baffle reduces the flow rate of gas to the QTA. Severe blockage can cause a pressure buildup in the reaction flask. Check the baffle regularly to make sure that none of the holes are blocked.

W4.5Warning: High Temperatures – Risk of BurnsThe burner head, QTA burner mount, and QTA can reach high temperatures. When you handle the mount or the QTA, wear flame- and heat-resistant

gloves or wait until the mount and QTA have cooled to room temperature.

Transfer tubeto reactor assembly

Baffle

4-6 0993-5288

MHS 15: Maintenance

QTA maintenance

The sensitivity that can be attained with the hydride-generation technique is critically dependent on the condition of the inner surface of the QTA. This is especially the case for the determination of arsenic, tellurium, and tin. The condition of the quartz inner surface can, under given circumstances, be responsible for a deterioration in the sensitivity. Under normal working conditions the inner surface of the QTA only requires cleaning if the sensitivity is significantly reduced, or if the QTA has become seriously contaminated (e.g. by solution from the reaction flask foaming over into it). If there is a marked decrease in the sensitivity, make sure that this is not due to other factors, such as unsuitable analytical parameters or instrument settings, or aged solutions, before you clean the inner surface of the QTA.Note: After prolonged use the inner surface of the QTA may become opaque. This is normal and does not affect the sensitivity.

Cleaning the inner surface of the QTA

1. Where applicable, tilt the QTA out of the flame and allow it to cool before removing it from the mount.

2. Carefully pull the transfer tube off the side inlet tube of the QTA.

3. Remove the graphite cooling rings from the ends of the QTA by very carefully pulling them out of the sleeves.Note: The graphite cooling rings are fragile. Handle them with care.

4. Remove the sleeves from the ends of the QTA.If the sleeves are difficult to remove, refer to page 4-12.

5. Wash the QTA out well in running water.Do not use sharp or pointed tools to scrape the inside of the QTA.

6. Rinse the QTA thoroughly with deionized water and then dry in a drying cabinet.



0993-5288 4-7

MHS 15: Maintenance

7. Refit the sleeves on the ends of the QTA and carefully insert the graphite cooling rings into the sleeves (more information: page 4-12).

8. Reconnect the transfer tube to the QTA and place the QTA back in the mount.

9. Perform a characteristic mass measurement. If cleaning has not improved the sensitivity, condition the QTA as described in the next section.

Conditioning the QTA

Note: The QTA is conditioned at the factory before shipment. Before you condition the QTA, make certain that there are no other causes for the loss in sensitivity, such as aged or contaminated calibration solutions or reductant solutions, or improper spectrometer settings.

Use a suitable plastic container for the hydrofluoric acid bath. The container should be suitably large so that you can place the QTA in the container and the acid level comes up to the side inlet tube. A plastic storage box from a PerkinElmer hollow cathode lamp is ideal for this purpose.

W8.1Warning: Hydrofluoric Acid – Risk of BurnsHydrofluoric acid (HF) is toxic, corrosive, and can cause severe burns. When using hydrofluoric acid, always wear suitable protective clothing

including a face mask, work in a fume hood, and observe the manufacturer’s instructions and your local safety regulations.

QTA

Hydrofluoric acid

Plastic container

4-8 0993-5288

MHS 15: Maintenance

1. Prepare the QTA as described in steps 1 through 5, above.

2. Carefully place the QTA in a bath of cold concentrated hydrofluoric acid and allow it to stand for 10–15 minutes.

3. Very carefully remove the QTA and thoroughly rinse it under running water.

4. Rinse the QTA thoroughly with deionized water and then dry in a drying cabinet.

5. Refit the sleeves on the ends of the QTA and carefully insert the graphite cooling rings into the sleeves (more information: page 4-12).


7. Check the characteristic mass.

0993-5288 4-9

MHS 15: Maintenance

Replacing worn parts

Gasket in the reaction flask socket

After prolonged operation, the gasket in the reaction flask socket may lose its resilience and cease to be gastight. You should replace the gasket when a good seal with the reaction flask is no longer provided.

Five replacement gaskets are provided with the instrument.

Transfer tube

Check the condition of the transfer tube between the reactor assembly and the QTA regularly. If it shows signs of deterioration, such as brittleness or cracks, or if it has become seriously contaminated, you should replace it.

Replace the transfer tube as follows:





Gasket in reaction flask socket

4-10 0993-5288

MHS 15: Maintenance

3. Carefully pull the transfer tube off the nozzle at the side of the reaction flask socket.

4. Pull the long and the short sections of transfer tube off the flashback arrestor.Discard the old transfer tube.

5. Take the replacement transfer tube and cut off a piece 5 cm long.Push this piece onto the body of the flashback arrestor.

6. Push the longer piece of transfer tube onto the screw-in cap of the flashback arrestor.

7. Carefully push the replacement transfer tube onto the nozzle at the side of the reaction flask socket.

8. Carefully push the end piece of the transfer tube onto the side inlet tube of the QTA.

Note: Use only original replacement transfer tubes. Do not use any other type of tube.

0993-5288 4-11

MHS 15: Maintenance

Sleeves on the QTA

After a long period of use, particularly at the temperatures involved, the sleeves retaining the graphite cooling rings tend to seal onto the quartz surface of the QTA. If this problem arises, do not apply force to remove the sleeves since you may break the QTA. Carefully cut off the old sleeves using a sharp scalpel.

Figure 4-1. QTA, sleeves and graphite rings

Replace sleeves as follows:



3. Remove the graphite cooling rings from the ends of the QTA by very carefully pulling them out of the sleeves.Note: The graphite cooling rings are fragile. Handle them with care.

4. Remove the sleeves from the ends of the QTA.If it is not possible to pull the sleeves off, carefully cut them off using a sharp scalpel.



Graphite ring

SleeveQTA

4-12 0993-5288

MHS 15: Maintenance

5. Fit new sleeves on the ends of the QTA. The sleeves are dusted on the inside with talcum powder; this aids fitting and reduces the tendency to sticking.

6. Carefully insert the graphite cooling rings into the sleeves.


0993-5288 4-13

MHS 15: Maintenance

4-14 0993-5288

Parts provided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3Obtaining supplies, replacement parts, and accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4Replacement parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

MHS 15: Parts and Supplies 5

5MHS 15: Parts and SuppliesMarker for header

Contents page

0993-5288 5-1

MHS 15: Parts and Supplies

5-2 0993-5288


Parts provided

PerkinElmer reserves the right to alter the schedule of parts provided without prior notice.

Qty. Item Part No.

1 MHS 15 reactor assembly . . . . . . . . . . . . . . . . . . . . . . . . B314-07631 QTA burner mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B300-03502 Quartz tube atomizers,

complete with graphite rings and sleeves . . . . . . . . . . . . B009-44142 Reaction flasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B009-41393 Covers for reaction flasks . . . . . . . . . . . . . . . . . . . . . . . . B009-41522 Plastic bottles, 500 mL . . . . . . . . . . . . . . . . . . . . . . . . . . B009-40321 Drip tray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B314-07351 Gas supply tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B007-98732 Replacement QTA sleeves (pack of 4) . . . . . . . . . . . . . . B050-58815 Gaskets for reaction flask socket . . . . . . . . . . . . . . . . . . B010-40491 Adhesive label ‘NaBH4’ . . . . . . . . . . . . . . . . . . . . . . . . . B010-40531 Adhesive label ‘SnCl2’ . . . . . . . . . . . . . . . . . . . . . . . . . . B010-40521 User’s Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0993-52881 Quick Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0993-5289

0993-5288 5-3


Obtaining supplies, replacement parts, and accessories

Supplies, replacement parts, and accessories can be ordered directly from PerkinElmer, using the part numbers quoted in this guide. PerkinElmer’s catalog service offers a full selection of high-quality atomic spectroscopy supplies through the Atomic Spectroscopy Supplies Catalog.

To place an order for supplies and many replacement parts, request a free catalog, or ask for information:– If you are located within the U.S., call toll free 1-800-762-4002, 8 a.m. to

8 p.m. EST. Your order will be shipped promptly, usually within 24 hours. – If you are located outside of the U.S., call your local PerkinElmer sales or

service office.

What is listed in this chapterThis chapter lists the most important replacement parts for MHS 15 system. Information about other parts and accessories is given in the current PerkinElmer brochures and price lists.

5-4 0993-5288


Replacement parts

Item Part No.

Reaction flask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . B009-4139Immersion tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . B009-4138Gasket for reaction flask socket . . . . . . . . . . . . . . . . . . .. . . . . . . B010-4049Transfer tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . B009-4140Flashback arrestor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . B009-8640Quartz tube atomizer, complete with graphite rings and sleeves. . . . . . . . . . . . .. . . . . . . B009-4415Quartz tube atomizer, without graphite rings or sleeves . . . . . . . . . . . . . . . . . . .. . . . . . . B009-4414QTA sleeves (pack of 4) . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . B050-5881Graphite cooling ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B009-4413Reductant bottle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . B009-4032Drip tray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . B314-0735

0993-5288 5-5


5-6 0993-5288

Unpacking and inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3Installing the QTA burner mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4Installing the reactor assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Connecting the inert gas supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6Preparing the reactor assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8

MHS 15: Installation 6

6MHS 15: InstallationMarker for header

Contents page

0993-5288 6-1

MHS 15: Installation

6-2 0993-5288


Unpacking and inspection

The MHS 15 is shipped in a single packing carton.

After you receive the instrument, unpack the components carefully:

1. Open the carton and remove packing materials.

2. Lift out the QTA Burner mount and the cartons containing small parts.

3. Carefully lift out the MHS 15 and place it on the bench.

4. Examine the components for any signs of damage during shipment.In the event of damage, file an immediate claim with the authorized carrier, and inform your local PerkinElmer office or representative.

A list of parts provided is given under ‘MHS 15: Parts and Supplies’ on page 5-3.

Carton recycling instructions

The carton can be folded down for easy storage. You can store the carton for future use (to transport the instrument), recycle it by returning it to PerkinElmer, or break it down completely and give it to your local recycling center.

0993-5288 6-3


Installing the QTA burner mount

To install the QTA burner mount (QTA=quartz tube atomizer) you must remove the burner head, attach the mount to the burner head, and then reinstall the burner head.

Remove the burner head

1. Where applicable, extinguish the flame, allow the burner head to cool, shut down the gases at source, and bleed the gas supply lines (the correct procedure is described in the User’s Guide for your AA spectrometer).

2. Remove the burner head as described in the User’s Guide for your AA spectrometer.

Attach the QTA burner mount Note: A heat shield is provided with the QTA burner mount. You only require the heat shield if your spectrometer is a Model 3100, 3110, or 3300.

1. Tilt the QTA bracket on the mount into the up position.

2. Slacken (but do not remove) the two adjusting screws in each securing clamp.

3. Slide the QTA burner mount onto the burner head and position the two securing clamps over the ends of the burner head. The QTA bracket must be at the front of the burner head.

4. Tighten the adjusting screws, but leave them slack enough so that you can move the mount.

Align the QTA burner mount

1. Tilt the QTA bracket into the down position.

2. Visually sight along the burner slot and move the QTA burner mount with respect to the burner head until the two ‘Vs’ in the QTA bracket line up with the burner slot.

3. Tighten the adjusting screws in the securing brackets.

W4.2Warning: High Temperatures – Risk of BurnsThe burner head can reach very high temperatures. Do not touch the burner head until it has cooled to room temperature.

6-4 0993-5288


Figure 6-1. Attaching the QTA burner mount to the burner head

Figure 6-2. Aligning the QTA burner mount on the burner head

Reinstall the burner head

1. Reinstall the burner head as described in the User’s Guide for your AA spectrometer.

Note: The QTA burner mount can remain permanently installed on the burner head. If you wish to change over to normal flame analyses, tilt the QTA bracket to the up position and ‘park’ the QTA in the holder at the back of the reactor assembly. Move the reactor assembly away from the immediate vicinity of the atomizer compartment.

QTA bracketin up position

Securing clamp(1 of 2)

Adjusting screw(2 each clamp)

Burner head

Burner headseen from therear

Burner slot

‘V’ in QTAbracket

QTA bracketin down position

0993-5288 6-5


Installing the reactor assembly

Connecting the inert gas supply What you need to provide

A suitable supply of argon or nitrogen. The gas must conform with the requirements listed in ‘MHS 15: Laboratory Requirements’ on page 7-6.

A suitable pressure regulator and on/off valve near to the system for the inert gas supply.

The gas supply system must comply with your local safety regulations.Refer also to the information given under ‘Handling compressed gases’ on page 1-9.

What is provided with the MHS 15

Gas supply tube, B007-9873

To connect the inert gas

The connector for the inert gas is located underneath at the rear of the reactor assembly.

Refer to Figure 6-3 on the following page.

1. Make sure that the gas supply is turned off.

2. Connect the gas supply tube to the argon (or nitrogen) pressure regulator. Use the R ¼'' screw connector provided or use a connector or adapter suitable for the gas regulator. Make sure that all the connections are secure.

3. Pass the gas supply tube to the rear of the reactor assembly. Make sure that the tube cannot be damaged or strained.

4. Connect the gas supply tube to the reactor assembly:1. Unscrew the nut from the connector and slide the nut onto the gas supply

tube.2. Push the gas supply tube onto the fitting on the connector.3. Screw the nut finger-tight back onto the connector.

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Figure 6-3. Connecting the inert gas

Inert GasGaz inerteInertgas

Pmin

2502.536

Pmax

3503.551

kPabarpsig

N or Ar only

Nur

2N ou Ar seulement

N oder Ar2

2

Inert gas supplynitrogen or argon

Gas supply tube

Connector forgas supply tube

0993-5288 6-7


Preparing the reactor assembly

Figure 6-4. MHS 15 reactor assembly and QTA

1. If not already done, place the drip tray onto the base of the reactor assembly.

2. Slip an immersion tube carefully over the capillary tube and onto the connector of the reaction flask socket.Note: Do not kink or damage the capillary tube.

3. Take the transfer tube (fitted with flashback arrestor) that emerges from the side of the reaction flask socket and carefully push the end piece of the tube onto the side arm of the QTA.

4. Place the QTA in the holder at the back of the reactor assembly.

Drip tray

Immersion tube

Connector

Reaction flask socketTransfer tube

Flashbackarrestor

QTA

6-8 0993-5288

Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3Gas supply requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Inert gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

MHS 15: Laboratory Requirements 7

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MHS 15: Laboratory Requirements

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Operating conditions

Operating requirements

The spectrometer and mercury/hydride system will operate correctly under the following conditions:

Indoors.

Ambient temperature +15 C to +35 C (+59 F to +95 F), with a maximum change not exceeding 2.8 C (5 F) per hour.

Ambient relative humidity 20% to 80%, without condensation.

Altitude in the range 0 m to 2000 m.

The location must be free of dust, smoke, and corrosive fumes.

Bench and location requirements

The location you choose for the spectrometer and mercury/hydride system must fulfil the criteria listed below:

Place the spectrometer on a sturdy bench or trolley (cart) capable of sustaining the weight. The work surface must be level, flat, clean, dry, and free from vibration. It should be strong and stiff enough to bear the weight of the spectrometer system over a long period without warping or bending. A movable table is very convenient, but make sure that the wheels can be securely locked.

Position the bench or trolley out of direct sunlight and away from radiators and heaters.

Position the system near to the electricity and gas supply points.

Position the system so that the atomizer compartment is located beneath a suitable fume ventilation system.

Make sure that there is space at the rear and sides of the system for air to circulate freely.


0993-5288 7-3


Make sure that there is sufficient room for you to work comfortably with the instruments, and that you can reach the connections at the rear of the instruments and the electricity and gas supply points.

Fume ventilation

You must provide an efficient fume ventilation system to remove the fumes generated by the atomizer. The specification for a suitable system is described in brochure no. L-301 – Preparing Your Laboratory for PerkinElmer Atomic Spectroscopy Instruments.This brochure is available from PerkinElmer.

Warning: Toxic Gases – Fume Ventilation SystemWithout adequate ventilation, potentially toxic vapors can build up in the laboratory. Your laboratory must have a reliable fume ventilation system before you use

this instrument.

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Gas supply requirements

The permanent installation of gas supplies is the responsibility of the user and should conform to local safety and building regulations. PerkinElmer recommends that cylinders be stored outside the laboratory and that gases be piped to the spectrometer system in approved gas lines.

The user must provide the gas supplies, regulators, connectors, and valves.Either the gas supplier or PerkinElmer can supply the correct regulators and valves.

You must be able to reach the on/off valves easily and see the pressure indicators.

Consult the chapter entitled ‘Safety and Regulatory Information’ for recommended safety procedures.

Warning: Compressed GasesHigh pressure gas cylinders can be dangerous if mishandled or misused. Always handle gas cylinders with caution and observe your local regulations

for the safe handling of gas cylinders.

0993-5288 7-5


Inert gas

The MHS 15 requires a supply of argon or nitrogen to operate the pneumatic system and to provide purging facilities. The specifications and requirements for the inert gas are listed in Table 7-1.

Set the outlet gauge pressure for the gas supply exactly to 250 kPa (Pmin).

Never set the outlet pressure to a value exceeding the maximum pressure (Pmax).

Note: Since the pressure of the inert gas to the MHS 15 has a slight influence on the flow rate of the gas through the system, always set the pressure consistently to 250 kPa.

Table 7-1. Specifications and Requirements for the Inert Gas

Gas Purity Outlet Gauge Pressure Max. Flowrate

kPa bar psigmL/min

(nominal) at 250 kPa

Pmin Pmax Pmin Pmax Pmin Pmax NaBH4 SnCl2

Argon 99.996% 250 350 2.5 3.5 36 51 700 1100

Nitrogen 99.996% 250 350 2.5 3.5 36 51 700 1100

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Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3Chemical vapor generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

The cold vapor technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6The hydride-generation technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6Literature on chemical vapor generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7

Principle of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11

MHS 15: System Description 8

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MHS 15: System Description

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Introduction

Figure 8-1. MHS 15 Mercury Hydride System – reactor assembly

The MHS 15 Mercury Hydride System is a manually-operated accessory for chemical vapor generation that allows the high-sensitivity determinations of mercury and the metallic hydride-forming elements by atomic absorption spectrometry. The MHS 15 comprises a reactor assembly and a quartz tube atomizer (QTA) assembly.

Reactor assembly

The reactor assembly is free-standing and is placed adjacent to the AA spectrometer. This assembly includes a reaction flask, a reservoir bottle for the reductant solution, and all pneumatic components for control of the carrier gas and transport of the analyte vapors to the QTA. A holder at the back of the reactor assembly allows you to ‘park’ the QTA when you are not using the system.The socket on the reactor assembly for the reaction flask includes a bayonet lock. The reaction flasks are provided with bayonet lugs so that you can easily attach and remove the reaction flasks from the reactor assembly.

Transfer tubeReductantbottle

Reaction flask

Flashback arrestor

to QTA

Plunger Reductant changeover valve

0993-5288 8-3


Quartz tube atomizer (QTA)

The QTA assembly consists of the quartz tube atomizer and a burner mount.

The burner mount installs on any PerkinElmer standard 10 cm burner head, thus permitting the QTA to be heated in the flame of the AA spectrometer. The QTA is located in the spectrometer’s sample radiation beam and can be aligned in the beam by means of the burner’s alignment controls. A hinged bracket on the burner mount allows you to tilt the QTA out of the flame.

The QTA resembles a cylindrical quartz cell. It has a central side tube inlet and is open at both ends. It is connected to the reactor assembly by a sample transfer tube. The QTA can be heated to about 1000 °C in the air-acetylene flame. Graphite cooling rings at the QTA ends prevent ignition of the hydrogen liberated during the determination when sodium tetrahydroborate is used as the reductant. In the unlikely event that the hydrogen should ignite, a flashback arrestor in the sample transfer tube prevents a flashback into the reaction flask.

If you wish to use the spectrometer for normal flame analyses, you can remove the QTA from the mount and ‘park’ it in the holder at the back of the reactor assembly. The burner mount can remain permanently installed on the burner head.Note: The QTA is referred to as the ‘quartz cell’ or ‘quartz tube’ in some publications.

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Figure 8-2. QTA mounted on the burner

Sample inlet

Hinged QTA bracket(shown in down position)

Burner head

Burner spraychamber

QTA

Transfer tubefrom reactor assembly

(nebulizer not shown)

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Chemical vapor generation

The cold vapor technique The cold vapor technique (CV AAS) is used for the determination of mercury. Depending on the form in which mercury is present in the test sample, the test sample is treated chemically (digested) to bring mercury into the ionic state in acidic solution. A reductant is dispensed into the test sample solution and mercury is reduced to the metallic state. Since mercury has an appreciable volatility even at ambient temperature, metallic mercury vapor can be driven from solution by a stream of inert gas and transported to the QTA, where its atomic absorption is measured.

The reductants used most commonly in the cold vapor technique are sodium tetrahydroborate (NaBH4) and tin(II) chloride (SnCl2).

The hydride-generation technique The hydride-generation technique (HG AAS) is used for the determination of the hydride-forming elements (As, Bi, Ge, Pb, Sb, Se, Sn, Te).The test sample is first treated chemically so that the analyte is present in ionic form in acidic solution. Sodium tetrahydroborate solution is dispensed into the acidic test sample solution. The reaction of sodium tetrahydroborate in acidic solution and the simultaneous reduction of the hydride-forming element can be described simply as follows:

BH4– + H3O+ + 2H2O ∫ H3BO3 + 4H2⟩ ϑΣΚ

and

3BH4– + 3H+ + 4H3AsO3 ∫ 4AsH3⟩=+ 3H2O + 3H3BO3 (2)

Equation 2 is representative for all of the hydride-forming elements. These two equations are coarse simplifications of the actual processes taking place.The volatile metal hydride (AsH3) is driven from solution by a stream of gas and transported to the heated QTA. The hydride decomposes in the QTA, the analyte is atomized, and its atomic absorption is measured.

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Literature on chemical vapor generation

The following monograph provides detailed information on chemical vapor generation and other aspects of atomic absorption analyses:

B. Welz and M. Sperling, Atomic Absorption Spectrometry,third, completely revised edition, Wiley-VCH, New York and Weinheim, 1999,ISBN 3-527-28571-7

0993-5288 8-7


Principle of operation

Figure 8-3. Schematic of pneumatic system

The MHS 15 is operated pneumatically. The system requires a supply of inert gas (argon or nitrogen) at an inlet pressure of 250 kPa (2.5 bar; 36–37 psig).

The system incorporates a pressure reducer that regulates the pressure of the incoming inert gas to the system to an overpressure of 10 kPa. From the pressure reducer the inert gas is split into three streams. One stream flows through flow restrictor F3 and through line a to the reaction flask. The second stream flows through flow restrictor F2 and through line b to the changeover valve. The third stream flows through inlet port 1 to outlet port 2 of the multipath valve and thence through flow restrictor F1 and line c to the changeover valve. Depending on the

NaBH4

SnCl2

F3 F2

F1

a

h

b

c

d

d

e

e

e

Inert gas

QTA

Pressurereducer

Multipathvalve

Changeovervalve

(in NaBH position)4

Changeovervalve

(in SnCl position)2

BurnerReductantreservoir

Reactionflask

Immersiontube

Flashbackarrestor

fg

g

1

2

4

8-8 0993-5288


setting of the changeover valve, the inert gas flows either through line d or line e to the reaction flask. If a reaction flask is not attached to the reactor assembly the inert gas escapes to atmosphere. When a reaction flask is attached, the inert gas flows through line f and escapes through the QTA. This gas flow purges the system free of air. Inert gas flows continuously as long as the gas supply is turned on.

To perform a determination, you attach the reaction flask containing the prepared measurement solution (blank solution, calibration solution, or test sample solution) to the reactor assembly, wait for air to be purged from the system (pre-reaction purge), and then depress and hold the plunger. While the plunger is depressed the gas stream from port 2 is shut off. Gas pressure is applied via port 1 to port 4 and then via line g to the reductant bottle. Reductant solution is forced through line h into the immersion tube and thence into the measurement solution. The stream of inert gas via F3 and line a through the immersion tube, together with the conical shape of the reaction flask, promotes good mixing of the reductant and measurement solutions. At the end of reductant addition this gas stream also purges the immersion tube free of reductant solution.Depending on the reductant you are using, one of the following processes takes place:

Sodium tetrahydroborate (NaBH4):

The changeover valve must be set to NaBH4 for this mode of operation.The violent reaction of the sodium tetrahydroborate solution with the acidic measurement solution and the liberation of hydrogen further aids in mixing the solutions. The reaction takes place and the metal hydride or the metallic mercury vapor is liberated and transported through the transfer tube f to the QTA by the stream of inert gas through F3 and line a, and also by the hydrogen liberated.

Tin(II) chloride (SnCl2):

The changeover valve must be set to SnCl2 for this mode of operation.Since hydrogen is not liberated during the reaction, an additional stream of inert gas is required through the immersion tube to promote mixing of the solutions and to drive out the metallic mercury vapor; this stream of gas comes via F2 and lines b and e to the immersion tube. The metallic mercury vapor is transported by the combined gas streams through the transfer tube f to the QTA.

0993-5288 8-9


You hold the plunger depressed for the reaction time determined during methods development (typically 20–30 s). You release the plunger at the end of this time. The flow of reductant solution to the reaction flask stops immediately and the purge gas stream via F1 resumes. The reaction proceeds rapidly to completion. You wait for the post-reaction purge time, after which you can remove the reaction flask and prepare the next sample.

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Technical data

Quartz tube atomizer (QTA)

165 mm long, 12 mm diameter.

QTA heating Up to approx. 1200 °C in the spectrometer’s air-acetylene flame.

Reaction flask Polypropylene, with special internal conical form. Connection to the reactor assembly via bayonet lugs.

Measurement solution volume

Max 50 mL prepared measurement solution.

Reductants Sodium tetrahydroborate (NaBH4) or tin(II) chloride (SnCl2).

Inert gas Argon or nitrogen.

Required inlet pressure

250–350 kPa (2.5–3.5 bar; 36–51 psig).

Max gas consumption Approx. 1100 mL/min in SnCl2 mode;approx. 700 mL/min in NaBH4 mode

Reactor assembly dimensions

170 mm wide x 160 mm deep x 375 mm high

Mass (weight) of reactor assembly

Approx. 4.3 kg

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Features of the MHS 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3Sample volume and dilution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3Purge gas function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4Calibration techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6

Chemical factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7

MHS 15: Analytical Notes 9

9MHS 15: Analytical NotesMarker for header

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MHS 15: Analytical Notes

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Features of the MHS 15

Sample volume and dilutionWith the MHS 15, the measured analyte signal is proportional to the mass of the analyte in the test solution and not to its concentration. The test solution can thus undergo substantial dilution without the risk of dilution errors occurring since the dilution is performed in the reaction flask. (In this guide the term ‘test solution’ is used generically for a blank solution, a calibration solution, or a test sample solution. The term ‘measurement solution’ refers to the solution being measured, i.e. the test solution that has been diluted.)

We make a clear distinction between the volume of test solution taken and the final total prepared measurement volume.

For satisfactory operation of the MHS 15 the minimum prepared measurement volume is 10 mL, while the maximum permitted measurement volume is 50 mL.

The volume of test solution can be from a few microliters up to the maximum permitted measurement volume of 50 mL.

Examples:

A 100 µL aliquot of a digestion solution is pipetted into the reaction flask and diluted with 10 mL dilute acid solution.Test solution volume = 100 µLPrepared measurement volume = 10 mL + 100 µL

In a water analysis a 10 mL test sample aliquot is taken for the determination without further dilution. In this case the test solution volume is the same as the prepared measurement volume.

It is essential that you measure the test solution volume accurately, using a suitable pipet. You can measure the diluent using a suitable measuring cylinder, since variations of ±1 mL in the prepared measurement volume are insignificant. Nevertheless you should avoid large variations in the prepared measurement volume since for every analyte element there is a given dependence of the sensitivity on the measurement volume.

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Purge gas function

The inert purge gas has two functions in the MHS 15:

To purge air from the system prior to the determination (pre-reaction purge).

To purge the analyte element from the system after the determination (post-reaction purge).

Pre-reaction purge

Since the function of the pre-reaction purge is different for the two operating modes, different principles apply to the selection of the pre-reaction purge time for each mode.

NaBH4 modeIf the system is not purged free of air before the reaction with NaBH4 is started, a potentially flammable air-hydrogen mixture may be formed. This mixture could ignite in the QTA when the temperature exceeds 500 °C. This is not dangerous, but interferes with the determination. The flashback arrestor reliably prevents a flame in the QTA from flashing back into the reaction flask. Thus after connecting the reaction flask to the reactor assembly, wait for the recommended pre-reaction time to allow the system to be purged free of air before adding NaBH4 solution. As a rule of thumb, the minimum pre-reaction purge time is 20–30 s.The analytical lines of arsenic (193.7 nm) and selenium (196.0 nm) are at wavelengths at which hot air exhibits an appreciable radiation absorption. For these two elements a relatively long pre-reaction purge time is required to remove all air from the system so that the absorption of air does not interfere in the determination. A loss in sensitivity has however been observed if the pre-reaction purge time is too long.For the determination of mercury, a loss in sensitivity may occur if the pre-reaction purge time is too long. The maximum pre-reaction purge time is 10 s.Since the QTA is not heated, it is unlikely that the air-hydrogen mixture will ignite.Recommended pre-reaction purge times are quoted in the recommended conditions for each element.

SnCl2 modeThis mode can be used for the determination of mercury, but not for the hydride-forming elements. A pre-reaction purge time is not required and you can add SnCl2 solution immediately after connecting the reaction flask to the reactor assembly.

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Post-reaction purge

Without gas purging at the end of the determination, some of the analyte element would remain in the system, leading to carryover problems. Thus at the end of the determination, do not remove the reaction flask from the reactor assembly until the system has been thoroughly purged with inert gas.Also, if the reaction flask is removed before the system has been purged, the hydrogen still present in the system may ignite.

NaBH4 modeAs a rule of thumb, the minimum post-reaction purge time is 40–50 s.

For heavy elements such as mercury, tellurium, and tin, longer times of typically 50–60 s are required to prevent carryover.

Recommended post-reaction purge times are quoted in the recommended conditions for each element.

SnCl2 modeA longer post-reaction purge time of typically 60 s is required to drive mercury from the system.

0993-5288 9-5


Calibration techniques

Calibration can be performed in terms of mass of the analyte or in terms of concentration of the analyte. There are thus two techniques of calibration.

Technique 1 – mass calibration

Prepare a single calibration solution containing 1 mg/L of the analyte. Pipet various volumes of the single calibration solution with a micropipet into 10 mL dilute acid in the reaction flask. The acid diluent can be measured with a measuring cylinder. Run the determination each time and establish a calibration plot of absorbance versus mass.

10 µL of 1 mg/L calibration solution 10 ng100 µL of 1 mg/L calibration solution 100 ng

Technique 2 – concentration calibration

Prepare suitably large volumes of a set of calibration solutions, each containing an appropriate concentration of the analyte.Pipet a 10 mL aliquot of each solution into the reaction flask and run the determination each time to establish a calibration plot of absorbance versus concentration.

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Chemical factors

InterferencesAnalyses using the mercury cold-vapor or hydride-generation techniques are largely free of chemical and matrix effects during the measurement stage since the analyte is separated from the sample matrix. Those interferences which may potentially occur are generally associated with sample preparation, or to interferences on the release of the metal hydride.Note: If you determine mercury using tin(II) chloride as the reductant, the apparatus will be contaminated with tin. If you subsequently determine tin in the same apparatus using sodium tetrahydroborate as the reductant, the tin contamination will interfere in the determination. Since tin is a hydride-forming element, the tin contamination may also interfere in the determination of other hydride-forming elements.If you change regularly between SnCl2 and NaBH4, we strongly recommend that you purchase a second MHS 15 and reserve it solely for use with SnCl2. Likewise you should reserve a set of reaction flasks, an immersion tube, and a reductant bottle solely for use with SnCl2.

Contamination The limits of detection attainable with the MHS 15 are often a function of the level of contamination present rather than the instrumental capabilities. When working in the 10–9 g range typical for the MHS 15, contamination can be a major source of error.Cautious handling of apparatus and careful technique will minimize this problem.Observe the following precautions to reduce the risk of contaminating the sample: Use only high-quality deionized water.

Take care that all materials in contact with the water are made of an inert plastic. Pure water, even when stored in PTFE, can leach impurities from the container in very short periods of time.

Chemicals used for sample preparation can be a major source of contamination. As far as possible, use only chemicals of analytical reagent grade.

Determine the reagent blank values of the reductant and other chemicals before using them.

Beakers, pipets, volumetric flasks, etc., are all major sources of metal contamination. As far as possible, use only inert plastics for sample handling.

0993-5288 9-7


Reagents and calibration solutions

The factors which can affect the generation of the hydride and the sensitivity can be as simple as not using freshly prepared reductant. The purity of all reagents used is critical when determining low levels of the hydride-forming elements. You must make sure that all reductants, acids and reagents are free from the analyte elements and any other elements which may react with the generated hydride.

Prepare NaBH4 reductant daily and preserve it by making it up in sodium hydroxide solution. Filter the reductant solution before use.

You can prepare calibration solutions by appropriate dilution of stock solutions.

Stock solutions with a concentration of 1000 mg/L or more are usually stable for one year.

Store stock and calibration solutions in inert plastic containers.

Prepare solutions with a concentration of 1 mg/L or less daily.

For all solutions with concentrations of less than 10 mg/L, check the water used for dilution and any acids or other added reagent for contamination with the analyte element.

Determine the blank concentration of the analyte element in the reducing agents and all other chemicals required for the analysis before use.

The stability of Hg calibration solutions can be severely affected by adsorption onto the walls of the storage container. Stabilize mercury calibration solutions by adding either potassium permanganate solution (KMnO4; concentration: 5 g/100 mL – add 5 drops per 50 mL) or potassium iodide solution (KI; concentration: 0.1 g/100 mL).Note: Do not stabilize mercury calibration solutions with KI if you are using SnCl2 as reductant since iodide interferes in the release of mercury when this reductant is used.

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The importance of testing the samples

Some samples exhibit behavior such as foaming or precipitation that can adversely affect the analytical results. A common problem is excessive foaming or precipitation when samples are mixed with NaBH4. To identify such problems, you should test unknown sample types before you use them in the system to determine if they produce foams or precipitates when you add the reagents you propose to use. You can perform these preliminary tests by working in a laboratory hood using a tall, open beaker.

Acidity of sample solutions

In the hydride-generation technique, the test sample solutions must be acidified. The Recommended Conditions contain details about the acids you should use.

Oxidation state of the analyte

The oxidation state of the analyte can affect the sensitivity. In solution, arsenic, selenium, antimony, bismuth and tellurium can all exist in one of two oxidation states. The oxidation state affects the rate at which the metal hydride is formed and thus the sensitivity. To ensure that all of the analyte exists in the same oxidation state, you should prereduce the calibration and test sample solutions when you determine the elements listed above. The Recommended Conditions contain details about the correct prereduction procedure for each element.

0993-5288 9-9


Foaming

Excessive foam production in the reaction flask can result in liquid entering the transfer tube and being transported into the QTA. If foam enters the transfer tube it can interfere with the transport of the hydride to the QTA. If this happens, you must clean and dry the transfer tube. If foam enters the QTA you must clean the inner surface of the QTA.

You can usually prevent excessive foaming by placing 1% of an antifoaming agent into the reductant solution. The following antifoaming agents have been successfully used in PerkinElmer applications laboratories.

Precipitation

Precipitates may be formed, for example, when protein-containing samples come into contact with acids or when samples with a high metal content come into contact with sodium tetrahydroborate. Precipitates can interfere with the determination.

If precipitation causes problems, you must perform appropriate digestions or separations to remove the offending constituent from such samples.

If heavy precipitation occurs, you should check to see that the addition of reductant solution or the inert gas stream has not been interrupted.

Antifoam Emulsion110ADow CorningMidland, MI 48601U.S.A.This is available from PerkinElmer as part number B050-7226

Silicone antifoaming agentType 7743Fa. E. Merck AG6100 DarmstadtGermany

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MHS 15: Translations of Warnings 10

10MHS 15: Translations of WarningsMarker for header

0993-5288 10-1

MHS 15: Translations

10-2 0993-5288


Translations of Warnings

This section contains translations of the safety conventions and warnings used in this guide.

dansk Oversættelser af advarslerDenne del indeholder oversættelserne af de advarsler, som er indeholdt i denne håndbog.

Deutsch Übersetzungen der WarnungenDieser Abschnitt enthält die Übersetzungen der in diesem Handbuch verwendeten Warnungen.

español Traducciones de las advertencias Esta sección contiene traducciones de las advertencias utilizadas en el presente manual.

italiano Traduzione dei simboli di avvertenzaLa presente sezione contiene la traduzione dei simboli di avvertenza utilizzati nel presente manuale.

Nederlands Vertalingen van de WaarschuwingenDit gedeelte bevat vertalingen van de waarschuwingen gebruikt in dit handboek.

português Traduções de avisosEsta secção contém traduções dos avisos usados no manual.

suomea Varoitusten käännöksetTämä osa sisältää tässä käsikirjassa käytettyjen varoitusten käännökset.

svenska Översättning av varningstexterDetta avsnitt innehåller översättningar av de varningstexter som används i handboken.

0993-5288 10-3


This symbol alerts you to situations that could result in personal injury to yourself or other persons.Details about these circumstances are in a box like this one.

dansk Dette symbol gør Dem opmærksom på situationer, som kan medføre kvæstelser af Dem selv eller andre personer.Detaljer vedrørende disse omstændigheder er indrammet på tilsvarende måde som denne henvisning.

Deutsch Dieses Symbol warnt vor Situationen, in denen Sie oder andere Personen verletzt werden können. Einzelheiten darüber sind in einem Rahmen wie diesem angegeben.

español Este símbolo le advierte de situaciones que pueden provocar lesiones corporales a usted o a otras personas. En los recuadros como éste se proporciona información sobre este tipo de circunstancias.

français Ce symbole vous signale des situations pouvant occasionner des dommages corporels à l'utilisateur ou à d'autres personnes.Les détails sur ces circonstances sont données dans un encadré semblable à celui-ci.

italiano Questo simbolo segnala situazioni che possono generare incidenti a voi stessi o ad altre persone.Troverete informazioni su tali circostanze in un riquadro come questo.

Nederlands Dit symbool maakt U attent op situaties die tot verwondingen voor Uzelf of anderen kunnen leiden.Bijzonderheden over deze omstandigheden staan in een kader zoals dit.

português Este símbolo alerta para situações que poderão causar um ferimento ao usuário.Detalhes referentes a estas circunstâncias encontram-se referidos numa caixa como esta.

suomea Tämä symboli haluaa kiinnittää huomiotasi tilanteisiin, joiden seurauksena voi olla itsesi tai muiden henkilöiden loukkaantuminen.Yksityiskohtaisia tietoja tällaisista tapauksista on tämäntapaisessa ruudussa.

svenska Denna symbol används för situationer där det finns risk för personskador om användaren inte följer anvisningarna.Detaljerad information ges i en ruta som denna.

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This symbol alerts you to the risk of hot surfaces that could cause personal injury to yourself or other persons.Details about these circumstances are in a box like this one.

dansk Dette symbol gør Dem opmærksom på risikoen for varme overflader, som kan medføre kvæstelser af Dem selv eller andre personer.Detaljer vedrørende disse omstændigheder er indrammet på tilsvarende måde som denne henvisning.

Deutsch Dieses Symbol warnt vor Gefahr durch heiße Oberflächen, durch die Sie oder andere Personen verletzt werden können. Einzelheiten darüber sind in einem Rahmen wie diesem angegeben.

español Este símbolo le advierte del peligro de que las superficies candentes provoquen quemaduras a usted o a otras personas. En los recuadros como éste se proporciona información sobre este tipo de circunstancias.

français Ce symbole vous avertit d'un risque de surfaces chaudes pouvant occasionner des dommages corporels à l'utilisateur ou à d'autres personnes.Les détails sur ces circonstances sont données dans un encadré semblable à celui-ci.

italiano Questo simbolo vi mette in guardia da superfici molto calde che possono causare incidenti a voi stessi o ad altre persone.Troverete informazioni su tali circostanze in un riquadro come questo.

Nederlands Dit symbool maakt U attent op het risico van hete oppervlaktes dat tot verwondingen voor Uzelf of anderen kunnen leiden.Bijzonderheden over deze omstandigheden staan in een kader zoals dit.

português Este símbolo alerta para um risco de superfícies quentes que poderão causar um ferimento ao usuário.Detalhes referentes a estas circunstâncias encontram-se referidos numa caixa como esta.

suomea Tämä symboli haluaa kiinnittää huomiotasi kuumiin pintoihin, joiden seurauksena voi olla itsesi tai muiden henkilöiden loukkaantuminen.Yksityiskohtaisia tietoja tällaisista tapauksista on tämäntapaisessa ruudussa.

svenska Denna symbol används för situationer där det finns risk för varma ytor som kan ge personskador om användaren inte följer anvisningarna.Detaljerad information ges i en ruta som denna.

0993-5288 10-5


Caution:The term CAUTION alerts you to situations that could result in serious damage to the instrument or other equipment.Details about these circumstances are described in a message similar to this one.

dansk Bemærk:Angivelsen CAUTION (BEMÆRK) gør Dem opmærksom på situationer, som kan medføre alvorlig ødelæggelse af apparatet eller andet udstyr.Detaljer vedrørende disse omstændigheder er beskrevet i henvisninger svarende til denne.

Deutsch Achtung:Der Ausdruck CAUTION (ACHTUNG) warnt vor Situationen, die eine ernste Beschädigung des Geräts oder anderer Systemteile zur Folge haben können.Einzelheiten darüber sind auf die gleiche Weise wie dieser Text hervorgehoben.

español Advertencia:El término CAUTION (ADVERTENCIA) le previene de situacones que pueden provocar averías graves en éste u otros equipos. En los recuadros como éste se proporciona información sobre este tipo de circunstancias.

français Attention:Le terme CAUTION (ATTENTION) vous signale des situations susceptibles de provoquer de graves détériorations de l'instrument ou d'autre matériel.Les détails sur ces circonstances figurent dans un message semblable à celui-ci.

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=Caution (continued)

italiano Attenzione:Con il termine CAUTION (ATTENZIONE) vi si mette in guardia da situazioni che possono comportare il serio danneggiamento della strumentazione o di altre apparecchiature.Troverete informazioni su tali circostanze in un riquadro come questo.

Nederlands Let op:De term CAUTION (LET OP) maakt U attent op situaties die tot ernstige beschadigingen aan het instrument of andere apparaten kunnen leiden.Bijzonderheden over deze omstandigheden worden beschreven in een mededeling gelijk aan.

português Atenção:O termo CAUTION (ATENÇÃO) alerta para situações que poderão causar danificação do aparelho.Detalhes referentes a estas circunstâncias encontram-se referidos numa caixa como esta.

suomea Huomio:CAUTION (HUOMIO) haluaa kiinnittää huomiotasi tilanteisiin, joiden seurauksena voi olla laitteen tai muiden varusteiden vakava vaurioituminen.Tällaiset tapaukset selostetaan yksityiskohtaisesti tämäntapaisessa huomautuksessa.

svenska Observera:Termen CAUTION (OBSERVERA) skall göra användaren uppmärksam på att apparaten eller annan utrustning kan ta allvarlig skada om anvisningarna inte följs. Detaljerad information ges i en ruta som denna.

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W1.2Warning: Unauthorized Adjustments and ServicingOnly a PerkinElmer service engineer or similarly trained and authorized person should be permitted to service the instrument. Do not attempt to make adjustments, replacements, repairs, or modifications to this

instrument except as described in the documentation supplied with the instrument.

dansk Advarsel: Ikke-tilladte indstillinger og arbejder på apparatetVedligeholdelse af apparatet er kun tilladt for PerkinElmer kundeservice-ingeniøren eller tilsvarende uddannede og autoriserede personer. Prøv ikke på at foretage indstillinger, udskiftninger, reparationer eller ændringer af

apparatet, som ikke er beskrevet i den dokumentation, der er vedlagt apparatet.

Deutsch Warnung: Unzulässige Arbeiten am GerätWartungs- oder Reparaturarbeiten oder Justierungen, die in der Benutzerdokumentation zum Gerät nicht beschrieben sind, dürfen nur vom PerkinElmer Kundendienst oder von entsprechend ausgebildeten und autorisierten Fachkräften ausgeführt werden.

español Advertencia: Ajustes y servicios sin autorización Tan sólo un ingeniero de Servicio Técnico de PerkinElmer o una persona de formación y autorización similares podrán realizar trabajos de revisión y mantenimiento del instrumento. No intente realizar ningún tipo de ajuste, sustitución o reparación en este aparato, a

excepción de lo descrito en la Documentación del Usuario que se adjunta.français Danger: Réglages et entretien non autorisés

Seul un ingénieur du service après vente PerkinElmer ou une personne autorisée et de même formation sont autorisées à intervenir sur l'instrument. Ne pas essayer d'effectuer des réglages, des remplacements, des réparations ou des

modifications sur cet instrument d'une manière autre que celle décrite dans la documentation fournie avec l'instrument.

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=Warning (continued) W1.2

italiano Pericolo: Regolazioni e manutenzione non autorizzatiL'asservimento dello strumento è permesso esclusivamente ad un tecnico di assistenza della PerkinElmer oppure da simile persona addestrata e autorizzata. Non provare ad eseguire regolazioni, sostituzioni, riparazioni o modifiche a questo

strumento se non come descritto nella documentazione allegata allo strumento.Nederlands Waarschuwing: Ongeautoriseerde aanpassingen en service

Alleen een PerkinElmer service-monteur of een gelijksoortig opgeleid en geautoriseerd persoon mag service verlenen aan het instrument. Probeer niet zelf aanpassingen aan dit instrument aan te brengen, het te repareren of

te veranderen behalve zoals beschreven in de documentatie die bij het instrument geleverd is.

português Aviso: Trabalhos não permitidos no aparelhoTrabalhos de manutenção apenas podem ser executados pelo Serviço Técnico da PerkinElmer ou por pessoal especializado devidamente formado e autorizado. Não tente realizar ajustamentos, substituições, reparações ou modificações neste

aparelho que não estejam descritos na documentação fornecida com o aparelho.

suomea Varo: Luvattomat säätö - ja huoltotyötLaitteen huoltotyöt saa antaa vain PerkinElmer -huoltoteknikoiden tai vastaavasti koulutettujen ja valtuutettujen henkilöiden tehtäväksi. Älä tee muita säätö-, vaihto-, korjaus- tai muutostöitä tässä laitteessa kuin sellaisia,

jotka on selostettu laitteen mukana toimitetussa dokumentaatiossa.svenska Varning: Icke tillåtna arbeten på apparaten

Endast servicepersonal från PerkinElmer eller personal med liknande utbildning och behörighet får utföra servicearbeten på apparaten. Underhålls- eller reparationsarbeten, justeringar eller ändringar som inte finns

beskrivna i användarmanualen till apparaten får inte utföras.

0993-5288 10-9


10-10 0993-5288



dansk Advarsel: Eksplosive omgivelserDette apparat er ikke konstrueret til brug i eksplosive omgivelser.

Deutsch Warnung: Explosionsfähige AtmosphärenDas Gerät darf nicht in explosionsfähigen Atmosphären betrieben werden.

español Advertencia: Atmósfera explosivaEste aparato no está diseñado para utilizarlo en atmósferas explosivas.

français Danger: Atmosphère explosiveCet instrument n'est pas conçu pour fonctionner dans une atmosphère explosive.

italiano Pericolo: Atmosfera esplosivaQuesto strumento non è concepito per operare in atmosfera esplosiva.

Nederlands Waarschuwing: Explosiegevaarlijke omgevingenDit instrument mag niet in een explosiegevaarlijke omgeving gebruikt worden.

português Aviso: Atmosferas explodíveisO aparelho não pode ser utilizado em atmosferas explodíveis.

suomea Varo: Räjähdysvaarallinen ympäristöTätä laitetta ei saa käyttää räjähdysvaarallisessa ympäristössä.

svenska Varning: Explosiv atmosfärApparaten är inte avsedd att användas i explosionsfarliga miljöer.

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W3.1Warning: UV Radiation – Risk of Eye DamageThe lamps may emit UV radiation which can damage your eyes. Do not gaze into a lighted lamp. Always wear UV-absorbing safety glasses when looking at the radiation from the

lamps.

dansk Advarsel: Ultraviolet stråling – farligt for øjneneLamperne kan emittere ultraviolet stråling, som kan forårsage øjenskader. Se ikke direkte ind i en tændt lampe. Bær altid beskyttelsesbriller, som absorberer ultraviolet stråling, når De ser ind i den

den lysende strålingskilde.

Deutsch Warnung: UV-Strahlung – Gefährdung der AugenDie Lampen emittieren UV-Strahlung in unterschiedlicher Stärke und können dadurch Augenschäden verursachen. Nicht mit ungeschützten Augen direkt in die leuchtenden Lampen schauen. Tragen Sie eine Schutzbrille, die die emittierte UV-Strahlung ausreichend absorbiert,

wenn Sie in die leuchtende Lampe schauen.español Advertencia: Radiación ultravioleta – Peligro de daños a los ojos

Las lámparas pueden emitir una intensa radiación ultravioleta que puede ser perjudicial para los ojos. No dirija la vista a una lámpara encendida. Use siempre gafas de seguridad que absorban este tipo de rayos.

français Danger: Rayonnement UVLes lampes peuvent émettre des UV susceptibles de provoquer des lésions oculaires. Ne pas regarder fixement une lampe allumée. Toujours porter des lunettes de protection absorbant les UV pour regarder le

rayonnement des lampes.

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italiano Pericolo: Radiazioni UV – Rischio di lesioni agli occhiLe lampade possono emettere radiazioni UV che possono lesionare gli occhi. Non guardare direttamente in una lampada accesa. Se guardate una lampada accesa indossate sempre occhiali di sicurezza in grado di

assorbire le radiazioni UV.

Nederlands Waarschuwing: Ultraviolette straling – Risico’s voor de ogenDe lampen kunnen UV-straling uitzenden die Uw ogen kan beschadigen. Staar niet in een brandende lamp. Draag altijd een veiligheidsbril die ultraviolette straling absorbeert wanneer U in de

brandende stralingsbron moet kijken.

português Aviso: Radiação UV – perigo para os olhosAs lâmpadas emitem uma radiação UV com intensidades diferentes podendo assim provocar ferimentos aos olhos. Não olhar directamente para uma lâmpada acesa. Use sempre óculos de protecção que absorvam suficientemente a radiação UV

emitida ao olhar directamente para a fonte de radiação luminosa.suomea Varo: UV-säteily – silmävammojen vaara

Lamput saattavat lähettää UV-säteilyä, joka voi vahingoittaa silmiä. Älä tuijota valaistuun lamppuun. Käytä aina UV-säteilyltä suojaavia suojasilmälaseja, kun katsot lampuista lähtevää

säteilyä kohti.svenska Varning: UV-strålning – risk för ögonskador

Strålningskällorna/lamporna alstrar UV-strålning som kan ge ögonskador. Titta inte in i en tänd strålningskälla/lampa. Använd alltid skyddsglasögon som absorberar UV-strålar när du tittar in i en tänd

strålningskälla/lampa.

0993-5288 10-13


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W4.2Warning: High Temperatures – Risk of BurnsThe burner head can reach very high temperatures. Do not touch the burner head until it has cooled to room temperature.

dansk Advarsel: Høje temperaturer – Fare for forbrændingerBrænderhovedet kan opnå meget høje temperaturer. Berør aldrig brænderhovedet, før det er kølet ned til stuetemperatur.

Deutsch Warnung: Verbrennungsgefahr Den heißen Brennerkopf nur mit hitzebeständigen Schutzhandschuhen anfassen oder

vor dem Anfassen auf Körpertemperatur abkühlen lassen. español Advertencia: Altas temperaturas – Riesgo de quemaduras

La cabeza del mechero puede alcanzar temperaturas muy altas. Asegúrese, antes de tocar el mechero, que éste se haya enfriado hasta alcanzar la

temperatura ambiente.français Danger: Températures élevées – Risque de brûlures

La tête de brûleur peut atteindre de très hautes températures. Ne pas toucher la tête de brûleur avant qu'elle ait refroidi à la température ambiante.

italiano Pericolo: Alte temperature – Rischio di ustioniLa testa del bruciatore può raggiungere temperature estremamente elevate. Non toccare la testa del bruciatore sino a che non si è raffreddato sino a raggiungere

temperatura ambiente.Nederlands Waarschuwing: Hoge temperaturen – Verbrandingsgevaar

De branderkop kan zeer hoge temperaturen bereiken. Raak de branderkop pas aan als hij tot kamertemperatuur is afgekoeld.

português Aviso: Altas temperaturas – perigo de queimadurasA cabeça do queimador pode alcançar temperaturas muito altas. Não toque na cabeça do queimador até ter alcançado a temperatura.

suomea Varo: Korkeat lämpötilat – palovammavaaraPolttimen pää voi saavuttaa korkeita lämpötiloja. Älä kosketa polttimen päätä, ennen kuin se on jäähtynyt

huoneenlämpötilaan.svenska Varning: Höga temperaturer – risk för brännskador

Brännaren kan nå mycket höga temperaturer. Vidrör inte brännarmunstycket förrän det har svalnat till rumstemperatur.

0993-5288 10-15


W4.5Warning: High Temperatures – Risk of BurnsThe burner head, cell holder, and QTA-cell can reach high temperatures. When you handle the cell holder or the QTA-cell, wear flame- and heat-resistant gloves

or wait until the cell and holder have cooled to room temperature.dansk Advarsel: Høje temperaturer – Fare for forbrændinger

Brænderhovedet, kuvetteholderen og QTA-kuvetten kan opnå høje temperaturer. Ved håndteringen af kuvetteholderen eller QTA-kuvetten skal man bære ikke-

brændbare, varmebestandige handsker eller vente, til kuvetten og holderen er kølet ned til stuetemperatur.

Deutsch Warnung: Verbrennungsgefahr Beim Hantieren mit der auf dem Brenner montierten Küvettenhalterung nichtbrennbare

hitzebeständige Schutzhandschuhe tragen oder vor dem Anfassen abwarten, bis Küvettenhalterung, Küvette und Brennerkopf auf Körpertemperatur abgekühlt sind.

español Advertencia: Altas temperaturas – Riesgo de quemadurasLa cabeza del mechero, el soporte de la célula y la célula QTA pueden alcanzar temperaturas elevadas. Al manejar el soporte de la cabeza del mechero de la célula QTA, utilice guantes

resistentes al calor y al fuego, o bien, espere hasta que célula y soporte se hayan enfriado hasta alcanzar la temperatura ambiente.

français Danger: Températures élevées – Risque de brûluresLa tête de brûleur, le porte-cellule, et la cellule QTA peuvent atteindre de hautes températures. Quand vous manipulez le porte-cellule ou la cellule QTA, portez des gants résistants

aux flammes et à la chaleur ou patientez jusqu'à ce que la cellule et son support aient refroidi à la température ambiante.

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italiano Pericolo: Alte temperature – Rischio di ustioniLa testa del bruciatore, il supporto della cella e la cella QTA possono raggiungere temperature etremamente elevate. Se manipolate il supporto della cella o la cella QTA indossate guanti antitermici ed

ignifughi oppure attendete sino a che la cella e il suo supporto si siano raffreddati sino a raggiungere temperatura ambiente.

Nederlands Waarschuwing: Hoge temperaturen – VerbrandingsgevaarDe branderkop, cuvettehouder en cuvette kunnen zeer hoge temperaturen bereiken. Bij het vastpakken van de cuvettehouder of de cuvette hittebestendige handschoenen

dragen of wachten tot de cuvette en de cuvettehouder tot kamertemperatuur afgekoeld zijn.

português Aviso: Altas temperaturas - perigo de queimadurasA cabeça do queimador, o porta-cubetas, e a cubeta QTA podem alcançar temperaturas elevadas. Ao manejar com o porta-cubetas ou a cubeta QTA, use luvas de protecção não

inflamáveis e resistentes ao calor, ou espere até que o porta-cubetas e a cubeta tenham alcançado a temperatura ambiente normal.

suomea Varo: Korkeat lämpötilat – palovammavaaraPolttimen pää, kyvetinpidike ja QTA-kyvetti voivat saavuttaa korkeita lämpötiloja. Kun käsittelet kyvetinpidikettä tai QTA-kyvettiä, käytä liekin- ja kuumuudenkestäviä

käsineitä tai odota, kunnes kyvetti ja pidike ovat jäähtyneet huoneenlämpötilaan.

svenska Varning: Höga temperaturer – risk för brännskadorBrännarmunstycket, skålhållaren och QTA-skålen kan nå mycket höga temperaturer. Använd icke-brännbara, värmebeständiga skyddshandskar vid hanteringen av

skålhållaren och QTA-skålen eller vänta tills skålen och hållaren svalnat till rumstemperatur.

0993-5288 10-17


W8.1Warning: Hydrofluoric Acid – Risk of BurnsHydrofluoric acid (HF) is toxic, corrosive and can cause severe burns. When using hydrofluoric acid, always wear suitable protective clothing including a face

mask, work in a fume hood, and observe the manufacturer’s instructions and your local safety regulations.

dansk Advarsel: Flussyre – Fare for ætsningerFlussyre (HF) er giftig, korrosiv og stærkt ætsende. Under brugen af flussyre skal man altid bære tilsvarende beskyttelsestøj, inklusive

ansigtsbeskyttelse, arbejde i et aftræk samt overholde producentens henvisninger og de stedlige sikkerhedsforskrifter.

Deutsch Warnung: Fluorwasserstoffsäure – VerätzungsgefahrFluorwasserstoffsäure (HF) ist giftig, stark ätzend und korrosiv. Tragen Sie beim Umgang mit Fluorwasserstoffsäure eine Schutzbrille oder

Gesichtsschutz, Schutzhandschuhe und säurebeständige Schutzkleidung und arbeiten Sie in einem Abzug. Beachten Sie die Gefahrenhinweise und Sicherheitsratschläge des Herstellers.

español Advertencia: Ácido fluorhídrico – peligro de quemaduras El ácido fluorhídrico (HF) es tóxico, corrosivo y puede causar quemaduras graves. Al usar este ácido, utilice siempre ropa de protección incluyendo una máscara facial;

trabaje en la campana de humos y siga las instrucciones del fabricante y las reglas de seguridad nacionales.

français Danger: Acide fluorhydrique – Risque de brûlureL'acide fluorhydrique (HF) est toxique, corrosif et susceptible de provoquer de graves brûlures. Lors de l'utilisation d'acide fluorhydrique, toujours porter une tenue protectrice

appropriée comportant un masque, travailler dans une hotte fermée et respecter les instructions du fabricant et les règlements de sécurité de l'entreprise.

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italiano Pericolo: Acido fluoridrico – Rischio di ustioniL'acido fluoridrico (HF) è tossico e corrosivo e può causare severe ustioni. Se utilizzate acido fluoridrico indossate sempre indumenti protettivi comprendenti una

maschera, lavorate in una cappa per fumi e osservate le istruzioni del produttore cosìccome le norme di sicurezza vigenti localmente.

Nederlands Waarschuwing: Fluorwaterstofzuur – EtsingsgevaarFluorwaterstofzuur (HF) is giftig, bijtend en sterk etsend. Draag tijdens het gebruik van fluorwaterstofzuur een veiligheidsbril of gezichtsmasker,

veiligheidshandschoenen en zuurbestendige veiligheidskleding en werk in een ruimte waarin wordt afgezogen! Neem de risicorichtlijnen en de veiligheidsvoorschriften van de fabrikant en die ter plaatse in acht.

português Aviso: Ácido fluorídico – perigo de queimadurasÁcido fluorídico (HF) é tóxico, corrosivo e pode causar queimaduras graves. Ao lidar com ácido fluorídico, use sempre vestuário de protecção, incluindo óculos ou

máscara de protecção, trabalhe dentro de um exaustor e respeite as instruções do fabricante bem como as regulamentações locais em matéria de segurança.

suomea Varo: Fluorivetyhappo – vaarana syöpymisvammatFluorivetyhappo (HF) on myrkyllistä ja syövyttävää ja se voi aiheuttaa vakavia syöpymisvammoja. Kun käsittelet fluorivetyhappoa, käytä aina sopivaa suojavaatetusta, johon kuuluu

myös naamari, työskentele vetokaapissa ja ota huomioon valmistajan antamat ohjeet ja paikalliset turvamääräykset.

svenska Varning: Fluorvätesyra – risk för brännskadorFluorvätesyra (HF) är giftig, frätande och kan ge svåra brännskador. Använd alltid skyddskläder och skyddsmask vid hantering av fluorvätesyra och arbeta

under en utsugningshuv. Följ tillverkarens instruktioner och de lokala säkerhetsföreskrifterna.

0993-5288 10-19


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0993-5288 In-1

Index

Index

In-2 0993-5288

Index

Aacidity of test samples 9-9aligning QTA burner mount on

burner head 6-4aligning the QTA 2-6analyte

oxidation state 9-9antimony

recommended conditions 3-13

arsenicestablishing pre-reaction purge

time 2-12recommended conditions 3-5

atomizer see quartz tube atomizer (QTA)

attaching reaction flask 2-10

Bbismuth

recommended conditions 3-7burner mount for QTA 8-4burner system

safe operation 1-13

Ccalibration solutions

preparing 9-6stability 9-8

calibration techniques 9-6carton recycling 6-3changeover valve 2-8, 8-9checklist

maintenance 4-4chemical vapor generation 8-6chemicals

safe handling 1-6, 3-3cleaning 4-4cleaning the QTA 4-7cold vapor technique 8-6

concentration calibration 9-6conditioning the QTA 4-8connecting inert gas supply 6-6contamination 9-7contamination with tin(II)

chloride 2-9, 9-7correct use of the instrument 1-4CV AAS 8-6

Ddisposing of

contents of waste containers 1-8, 4-5

reaction residues 1-8, 4-5

Eenvironment

operating conditions 1-5storage conditions 1-5

Fflame

safe operation 1-13flame operation

safe use of burner gases 1-12foaming 9-10fume ventilation 7-4

Ggas supply requirements 7-5gasket in reaction flask socket

replacing 4-10

Hhazards with flame operation

high temperatures 1-13UV radiation 1-13

hazards with mercury/hydride systems

hazardous chemicals 1-14high temperatures 1-14toxic products 1-14

HG AAS 8-6hydride-forming elements 8-6hydride-generation technique

8-6hygiene 1-5

Iinert gas

connecting supply 6-6pressure 7-6requirements 7-6

installing QTA burner mount 6-4

installing the reactor assembly 6-6

internal servicing 4-3

Llaboratory hygiene 1-5laboratory requirements

fume ventilation 7-4gas supplies 7-5operating conditions 7-3

laboratory ventilation 1-5literature on chemical vapor

generation 8-7

Mmaintenance 4-4

cleaning the QTA 4-7conditioning the QTA 4-8external surfaces 4-4gasket in reaction flask socket

4-10replacing sleeves on QTA

4-12transfer tube 4-10

mass calibration 9-6measurement solution 8-9, 9-3measurement volume 9-3measurements 2-10

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Index

mercurycalibration solutions 9-8recommended conditions

(NaBH4) 3-9recommended conditions

(SnCl2) 3-11mercury determination 8-6mercury/hydride systems

hazards 1-14safety practices 1-14

method for spectrometer 2-4methods development 2-12

establishing post-reaction purge time 2-13

establishing pre-reaction purge time 2-12

establishing reaction time 2-13

establishing read time 2-13MHS 15

description 8-3technical data 8-11

Ooperating conditions 1-5, 7-3operating mode 2-8, 8-9, 9-4operating principle 8-8oxidation state 9-9

Pparts provided 5-3performing measurements 2-10PerkinElmer service 4-3placing QTA in QTA bracket

2-3positioning the MHS 15 2-3post-reaction purge 8-10, 9-5post-reaction purge time

establishing 2-13precipitates 9-10

prepared measurement volume 9-3

preparing for analyses 2-4pre-reaction purge 8-9, 9-4

establishing time 2-12principle of operation 8-8purge gas

function 9-4see also inert gas

purging (flushing) the reductant transport system 4-5

QQTA

aligning 2-6cleaning the inner surface 4-7conditioning 4-8description 8-4placing in bracket 2-3

QTA burner mount 8-4aligning on burner head 6-4installing 6-4

quartz tube atomizer see QTA

Rreaction flask

attaching 2-10reaction time

establishing 2-13reactor assembly

description 8-3installing 6-6

read timeestablishing 2-13

reagentspurity 9-8

recommended conditionsantimony 3-13arsenic 3-5bismuth 3-7mercury (NaBH4) 3-9

mercury (SnCl2) 3-11selenium 3-15tellurium 3-19tin 3-17

reductant changeover valve 2-8, 8-9

reductant transport systempurging (flushing) 4-5

references for laboratory safety practice 1-16

replacement parts 5-5obtaining 5-4

replacementsgasket in reaction flask socket

4-10sleeves on QTA 4-12transfer tube 4-10

routine maintenance 4-4

Ssafe handling of chemicals 1-6,

3-3sodium tetrahydroborate 1-7,

3-3safe operation of the flame 1-13safety

correct use of the instrument 1-4

handling chemicals 1-6, 3-3operation of the flame 1-13

safety conventions 1-3safety practices

mercury/hydride systems 1-14

references 1-16samples

acidity 9-9analyte oxidation state 9-9testing 9-9

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Index

seleniumestablishing pre-reaction purge

time 2-12recommended conditions

3-15service 4-3setting up the system 2-3sleeves on QTA

replacing 4-12sodium tetrahydroborate 1-7,

3-3spectrometer method 2-4storage conditions 1-5symbols used in the guide 1-3

Ttechnical data 8-11tellurium

recommended conditions 3-19

test solution 9-3tin

contamination 2-9, 9-7recommended conditions

3-17transfer tube

replacing 4-10

Uunpacking 6-3

Vventilation, laboratory 1-5

Wwaste disposal

contents of waste containers 1-8, 4-5

reaction residues 1-8, 4-5

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Index

In-6 0993-5288

manual usuario fias mhs15

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