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GE Newsletter June 2017

Application Spotlight In 2016 the Direct Connect (DC) nebulizer product line was released, combining the benefits of our proprietary UniFitTM zero dead volume sample connector and full-length VitriCone capillary10 with an improved gas connection assembly. The features of the SeaSpray DC nebulizer are summarized in Figure 12. Figure 12. Features of SeaSpray DC Nebulizer. Full length - thick walled VitriConeTM Sample Channel Machined exterior Inert metal-free argon connector Instrumentspecific provides optimum aerodynamics Polished “selfwashing” “Direct Connect” argon line UniFit sample tube connector Secure ratchet connection tip Elegra - DuraMist DC - Twister - D-Torch 1.10 1.08 1.06 1.04 1.02 1.0 Normalized Intensity To 0.98 evaluate the performance of the SeaSpray DC nebulizer a 1 ppm 0.96 multi-element standard was prepared in a 3.5 % NaCl matrix and 0.94 0.92 aspirated at 1 mL/min for 9 hours with no rinsing. The test was carried 0.9 out on an Agilent 5100 SVDV ICP-OES instrument. The combination 19 25 of the 57 SeaSpray 89 DC 121 nebulizer,152 Twister 184 spray 216 chamber, ceramic D-Torch, and Elegra Time argon (minutes) humidifier provided exceptional stability (Figure Ba 13).455.403 A measurement Mn 257.610 was taken approximately Zn 213.857 every 3 mins over a period of 9 hours, while a precision (%RSD) of less than 1 % was maintained throughout the experiment. Figure 13. Long term stability test, 9 hour analysis of 1 ppm standard in 3.5 % NaCl. Elegra - SeaSpray DC - Twister - D-Torch Wavelength Precision (% RSD) Zn 213 0.8 Mn 257 0.6 Mg 280 0.6 19 78 153 228 303 378 453 528 Time (minutes) 1.10 1.08 1.06 1.04 1.02 1.0 0.98 0.96 0.94 0.92 0.9 Mg 280.270 Mn 257.610 Zn 213.857 Normalized Intensity To complement the SeaSpray, the inert DuraMist nebulizer was introduced in 2011.11 The DuraMist is also a concentric nebulizer, designed with a PEEK capillary insert and PEEK body capable of handling up to 30% TDS and up to 5% hydrofluoric acid (HF). The strength and rigidity of the PEEK material allows the DuraMist to be manufactured to very tight tolerances, enabling it to closely match the performance of the SeaSpray, but in an inert design. To evaluate the performance of the DuraMist DC nebulizer a similar experiment was conducted, only this time a 1 ppm multi-element standard was in a 10.0 % NaCl matrix and aspirated at 1 mL/min for 4 hours with no rinsing. The DuraMist DC nebulizer was combined with the same “High TDS” application kit that was used in the SeaSpray experiment, with a measurement taken every minute over a period of 4 hours (Figure 14). Results with the DuraMist are also exceptional, as a precision (%RSD) of less than 1 % was maintained throughout the experiment. Figure 14. Long term stability test, 4 hour analysis of 1 ppm standard in 10.0 % NaCl. Elegra - DuraMist DC - Twister - D-Torch Wavelength Precision (% RSD) Zn 213 0.8 Mn 257 0.5 Ba 445 0.9 19 25 57 89 121 152 184 216 Time (minutes) 1.10 1.08 1.06 1.04 1.02 1.0 0.98 0.96 0.94 0.92 0.9 Ba 455.403 Mn 257.610 Zn 213.857 Normalized Intensity Reducing Sample Load and Increasing Washout Efficiency In our evaluation of Elegra the SeaSpray - SeaSpray and DC DuraMist - Twister -nebulizers D-Torch a rinse was not utilized in-between each sample. The rinse was purposely eliminated from the ICP method to focus on each nebulizer’s high tolerance to TDS. However, with any high TDS application it is recommended that you increase your rinse time between samples to provide improved performance and long term stability. It is also recommended that you reduce the sample uptake rate to as low as your detection limits allow to minimize the amount of sample transported to the plasma. Lowering the sample uptake will reduce the rate of devitrification to the quartz torch and frequency of cleaning the ICP-MS cones. However, longer rinse times combined with a lower sample uptake can add significant time to your analysis. Some of this additional time can be easily eliminated from your method with the Niagara CM Rapid Rinse accessory (Figure 15), which begins rinsing the nebulizer and spray chamber the instant the sample measurement is completed and continues to rinse until the next sample is ready. This economical and simple 4-port switching valve carries out the rinse cycle during the time that is usually wasted waiting for the sample to reach the nebulizer (commonly referred to as the uptake delay) and subsequently void to waste. The fast pump option that is typically employed to reduce the uptake delay time puts excess stress on the nebulizer and ICP sample introduction system by running at high flow rates that exceed the recommended operating conditions. With the Niagara the fast pump can be employed with no negative effects, since the sample is directed to waste during the uptake delay. The Niagara rinse tubing calculator will also calculate the correct size 19 78 153 228 303 378 453 528 Time (minutes) 1.10 1.08 1.06 1.04 1.02 1.0 0.98 0.96 0.94 0.92 0.9 Mg 280.270 Mn 257.610 Zn 213.857 Normalized Intensity www.geicp.com Glass Expansion Newsletter | Issue 43 5


GE Newsletter June 2017
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