A New Versatile Programmable Temperature Spray Chamber for ICP Jerry Dulude and Ron Stux (USA), Vesna Dolic (Australia),

1. Without IsoMist IsoMist At 21C Figure 2: Effect of spray chamber temperature on the % CeO ratio by ICP-MS Figure 3: Effect of spray chamber temperature on sensitivity using an IsoMist with ICP-OES Encapsulated spray chamber Table 1: Consecutive runs (90 minutes apart) of straight naphtha by ICP-OES with IsoMist at -10C IsoMist Accessory Figure 4: Effect of spray chamber temperature on LOD using an IsoMist with ICP-OES Software control panel A New Versatile Programmable Temperature Spray Chamber for ICP Jerry Dulude and Ron Stux (USA), Vesna Dolic (Australia), Glass Expansion (www.geicp.com) Introduction Low Temperature Applications Elevated Temperature Applications Constant Temperature Benefits 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. Two low temperature control applications are investigated. Reduction of oxide interferences in ICP-MS Direct aspiration of naphtha, a volatile organic solvent that severely loads the plasma. 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. 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. Description • 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 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. Figure 5: Long-term drift in ICP-OES with and without temperature control Figure 1: IsoMist™ Programmable Temperature Spray Chamber DISCUSSION and CONCLUSIONS • Clearly, 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. 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.