NEWS Figure 2c: Airtight seal of the IsoMist spray chamber in its case Figure 4: PCC Spray Chamber mounted on an Agilent 7700 ICP-MS manufacturers rely on their standard spray chamber design to be fitted in a packing foam. This type of design can lead to unstable temperatures and an uneven temperature with respect to the top and bottom of the spray chamber. The importance of a stable spray chamber temperature is demonstrated by Figure 3, which shows that a spray chamber temperature change of 1oC can result in a sensitivity change of 3%. In order to ensure an accurate and constant spray chamber temperature, the IsoMist Programmable Temperature Spray Chamber is preferable. Peltier Cooled Cyclonic (PCC) Spray Chamber for Agilent ICP-MS: When the best temperature flexibility or temperature stability is required, we recommend the IsoMist. However, for many ICPMS applications, a fixed temperature of 2 or 5°C is used with no required flexibility. For these applications, we recommend the PCC Spray Chambers for the Agilent 7700/7900/8800 (Figure 4) and 7500 ICP-MS models. The PCC is based on the spray chamber and Peltier system of the IsoMist but is coupled to the electronics and water cooling of the Agilent ICP-MS and operated via Agilent software. Therefore Agilent 7700/7900/8800 and 7500 users can get the benefit of a cyclonic spray chamber, faster washout and increased sample throughput compared to the Scott style spray chamber. Evolution of the Spray Chamber-Nebulizer Interface: The interface between the nebulizer and the spray chamber in an ICP spectrometer needs to fulfill several criteria: 1. Seal the spray chamber from the external environment 2. Ensure that the nebulizer is always in the same position 3. Allow the nebulizer to be easily removed to be cleaned or replaced 4. Not contaminate the sample 5. Minimize carryover from one sample to the next With early spray chambers, an attempt was made to satisfy these criteria by constructing the spray chamber with a glass arm Figure 3: Average normalized intensity of 18 analyte lines vs. spray chamber temperature containing grooves for o’rings as shown in Figure 5A. Evolution of the Spray Chamber-Nebulizer Interface: Figure 5: Progression of spray chamber-nebulizer interfaces; all glass with o’rings (A), plastic adaptor with o’rings (B), and Helix o’ring-free adaptor (C). www.geicp.com Glass Expansion Newsletter | Issue 35 3
GE0283 GE Newsletter October 2014
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