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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Food Composition and Methods Development Laboratory » Research » Publications at this Location » Publication #144292


item Yanes Santos, Enrique
item Miller-Ihli, Nancy

Submitted to: Spectrochimica Acta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/2003
Publication Date: 5/6/2003
Citation: Yanes Santos, E.G., Miller-Ihli, N.J. 2003. Characterization of microconcentric nebulizer uptake rates for capillary electrophoresis inductively coupled plasma mass spectrometry. Spectrochimica Acta. 58:949-955

Interpretive Summary: There is interest in combining capillary electrophoresis (CE) with inductively coupled plasma mass spectrometry (ICP-MS) for speciation determinations. Two challenges that are faced are sample injection and interfacing the two techniques. In this study, microconcentric nebulizers are characterized and their usefulness evaluated. A major conclusion was that the commercial nebulizers studied, produced much higher sample uptakes than the manufacturer's specifications and there was significant variability between different nebulizers of the same model. A phenomenon observed in this work and previously reported by others, in which increasing nebulizer gas flow led to decreased sample uptake rates, was evaluated extensively and we provided an explanation for the first time. Research scientists in academia and government interested in combining CE with ICP-MS will find this manuscript useful because it provides a step-by-step method for characterizing nebulizer uptake rates.

Technical Abstract: There is demonstrated interest in combining capillary electrophoresis (CE) with inductively coupled plasma mass spectrometrty (ICP-MS) to do speciation determinations. When self-aspirating nebulizers are used for this application, it is important to offset the suction effect to avoid degradation of the separation. In this study, sample uptake rates for three Microconcentric nebulizers of the same model, in combination with a cyclonic spray chamber, were characterized and compared for future utilization in CE-ICP-MS interfaces. The specific model studied was a MicroMist with a nominal uptake rate of 100 microliters/min at 1 L/min argon gas per the manufacturer's specifications. Sample uptake rates at various nebulizer gas flows were measured by aspirating water from a weighed container and calculating the uptake rate in microliters/min. The nebulizers studied provided good reproducibility from day to day, but a comparison of the different nebulizers reflected a significant difference in performance. A characteristic observed during the study was that uptake rates decreased with increasing nebulizer gas flow. This can be used for sample introduction for CE-ICP-MS. Interestingly, very different performance was observed when comparing the three different nebulizers of the same model. Uptake rates showed strong dependence on argon gas flow rates and the dimensions of the sample uptake tubing.