Elemental Analysis Service

Heriot Watt University

Christina Graham

What is Elemental Analysis?

Elemental analysis is the determination of the percentage of an element in a sample

Our instrument the CE 440 analyses for the elements carbon, hydrogen, and nitrogen

Other elements can be done externally

Schematic DiagramExeter CE-440 Elemental Analyser

O

He

2Combustion Reduction Mixing

Area

SampleVolumeDetectors

Tube Tube

How will the service operate?

One day a week All samples submitted the previous

day in the sample bottle provided All samples accompanied by a

completed request form Results and sample returned to you

the next day

Risk / Hazard assessment Please specify if sample is harmful (specify) /

volatile / hygroscopic / air sensitive / scarce / etc.

%C

%H %N

Formula

Theoretical Information

* Please draw approximate structure * on reverse side of submission form

Date of Analysis Operator

Results

Comments

Assay No.

%C %H %N

Name User / Sample Code

Supervisor

Department

Telephone

E-mail Date Submitted Tick box if duplicate analysis is required

General Information

* Users outwith the University should * specify the company and address on the reverse side of submission form

Christina Graham, Elemental Analysis Service, Department of Chemistry, Heriot-Watt University, Edinburgh, EH14 4AS

Tel 0131 449 5111 Ext.4233, E-mail ChristinaGraham@hw.ac.uk

Elemental Analysis Request Form Department of Chemistry Heriot- Watt University

Project Code

Request Form

Your sample code should consist of your initials and a number that refers to an individual sample.

Give the formula or at least an indication Deduce your %CHN content It is very useful draw the structure on the

back of the form It is essential to complete the hazard

assessment

How much sample do I need?

If your hydrogen content is <3%3.0mg

If your hydrogen content is >3%2.0mg

Samples having a large residue of the order 50% - up to 5mg

Excess sample is always returned

Good Working Practice

Ensure that your sample is as pure as it can possibly be

Sample must be free from solvent

Submit samples regularly and on time

Make sure you hand in enough sample

Solvent Purity

Example - A sample of phenyl hydrazine (1.6mg) containingapprox. 2% w/w methanol.

C6H5NHNH2 - 108.14 g/mol

1.6mg 'sample' is actually -1.568mg Phenyl hydrazine (1.450 x10-2 mmol)

0.032mg MeOH (9.988 x10-4 mmol)

Theoretical formula - C6H8N2Actual formula - C6H8N2. 0.069MeOH = C6.069 H8.276 N2O0.069

%C %H %NTheoretical 66.62 7.47 25.91Actual 66.04 7.57 25.39

Elemental Analysis Total Usage Jan 2000- July 2004

Total

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50

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Jan May Sep Jan May Sep Jan May Sep Jan May Sep Jan

Take care and try to get it right first time!!

For publishable results each element must be within + 0.3%

If sample result is poor you would have to re-purify, dry and resubmit

this costs time, money and is unfair to others

Some points to note

Cost of an internal sample is £3 Cost of an external sample is £9 - £15

for a duplicate Keep a note of your sample code and

assay number - a computer record and hard copy will be kept for 5 years

Online help

Home page is http://www.che.hw.ac.uk/research/services/chn.html

%CHN calculator Solvent correction calculator On-line request form

Please don`t say to me!! Sample is totally pure

as the NMR is perfect Is the instrument

working properly? Urgent sample - only

10 of them! Not too worried about

the result - just a quick check I have the right stuff!!!

Good Luck with your research!!!

Looking forward to analysing your samples!!!

Thank you for your time today!!!!