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A New Versatile Programmable Temperature Spray Chamber for ICPJerry Dulude and Ron Stux (USA), Vesna Dolic (Australia), Glass Expansion (www.geicp.com)

For both ICP-OES and ICP-MS, the temperature of the spray chamber can have a profound influence on the ability of the system to achieve high quality results in a variety of sample types. This paper describes a novel system that both monitors and controls spray chamber temperature, and evaluates the device under a variety of conditions for a variety of applications. All ICP-MS work was performed on a PerkinElmer Elan 6000 and all ICP-OES work on a PerkinElmer Optima 2100 DV.

Introduction

Description

Figure 1: IsoMist™ Programmable Temperature Spray Chamber

The IsoMist Programmable Temperature Spray Chamber is shown below and has the following characteristics:•Programmable from -10 to +60C in 1degree increments•Maintains temperature to within 0.1 degree C•Compact design (7.5x4x4 inches)•100% self-contained (no external water lines)•Communicates via wireless Bluetooth technology or USB•Compatible with all ICP-OES & ICP-MS models

Increasing spray chamber temperature increases the transport efficiency of the sample introduction system. At typical uptake rates of 1 to 2 ml per minute, this would result in an unstable plasma. However, when sample volume is limited as is often the case in certain clinical samples, very low uptake rates must be used. In this case increasing the spray chamber temperature will not overload the plasma and will allow lower detection limits to be reached as shown below. Data taken under standard conditions.

Elevated Temperature ApplicationsLow Temperature ApplicationsTwo low temperature control applications are investigated.Reduction of oxide interferences in ICP-MSDirect aspiration of naphtha, a volatile organic solvent that severely loads the plasma.

DISCUSSION and CONCLUSIONSClearly, the effect of spray chamber temperature on performance for both ICP-OES and ICP-MS is profound. For a variety of reasons, however, this parameter has not been accurately controlled in many situations, particularly for ICP-OES. These reasons include the following:

• The unruliness and messiness of external chiller systems that have been employed with jacketed spray chamber

•The unavailability of customized chamber control systems for all models

With the advent of the IsoMist Programmable Temperature Spray Chamber, the above reasons go away. This enables the ICP-OES and ICP-MS analyst to customize a method with respect to all important parameters including spray chamber temperature.

Figure 5: Long-term drift in ICP-OES with and without temperature control

Constant Temperature Benefits

IsoMist AccessoryIsoMist Accessory

EncapsulatedEncapsulatedspray chamberspray chamber

Software controlSoftware controlpanelpanel

Figure 2: Effect of spray chamber temperature on the % CeO ratio by ICP-MS

Table 1: Consecutive runs (90 minutes apart) of straight naphtha by ICP-OES with IsoMist at -10C

Figure 4: Effect of spray chamber temperature on LOD using an IsoMist with ICP-OES

0

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. DL 2ml/min 21C

.02ml/min 21C

.02ml/min 60C

Figure 3: Effect of spray chamber temperature on sensitivity using an IsoMist with ICP-OES

0.00

0.50

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40C

60C

21C ISOMISTLong term stability for STD2 at 21 deg for over 3 hours

2 mL/min sample uptake

0.95

0.97

0.99

1.01

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11 30 70 123 190

Time(min)

No

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iss

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co

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ts

Al 396.153Al 394.401Be 313.107Cd 214.440Cd 226.502Co 238.892Cr 267.716Cr 205.560Cu 327.393Cu 324.752Fe 238.204Mn 257.610Ni 231.604Ni 221.648Pb 220.353Se 196.026V 292.464Zn 206.200Zn 213.857Zn 202.548

O30SS2111777 sample uptake 2.0mL/min

0.95

0.97

0.99

1.01

1.03

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8 74 164 198 233 262 277

Time (min)

Al 396.153As 188.979Ba 233.527Ca 317.933Cr 267.716Cu 327.393K 766.490Mg 280.271Mn 257.610Mo 202.031Na 589.592Ni 231.604P 213.617S 181.975Si 251.611Zn 206.200

Without Without IsoMistIsoMist

IsoMistIsoMistAt 21CAt 21C

Signal drift is closely associated with the drift of spray chamber temperature. Initially as the spectrometer warms up, there is a constant upward drift in temperature. Subsequently, the spray chamber temperature drifts along with the environmental temperature of the laboratory. The figure below shows how stabilizing the spray chamber temperature has a dramatic effect on stabilizing the analytical signal over the long term.

Data generated on a Sciex6000 ICP-MS at 1.1L/min argon nebulizer flow using a Conikal nebulizer and Twister spray chamber. RF power was 1400 watts.

1500 watts on PE2100DV; SeaSpray nebulizer and Twister spray chamber; Neb gas at 0.35LPM, uptake at 0.3ml/min; 1mm bore injector. Coolant gas flow was 20LPM; AUX flow was 1.8LPM.