Low temperature hydrogen plasma assisted chemical vapor generation for Atomic Fluorescence Spectrometry

Chemical vapor generation techniques have long been considered as important ways of sample introduction for analytical atomic spectrometry. In this paper, a low temperature plasma assisted chemical vapor generation method which avoids the massive use of consumptive chemical agents was proposed by using atmospheric pressure dielectric barrier discharge. The plasma was generated by hydrogen doped argon gas flow through a quartz tube, serving as a dielectric barrier, which had a copper wire inner electrode and a copper foil outer electrode. An alternative high voltage was applied to electrodes to ignite and sustain the plasma. Sample solutions were converted to aerosol by a nebulizer and then mixed with the plasma to generate hydrides. To confirm the utility of this method, four hydride forming elements, As, Te, Sb and Se, were determined by coupling the low temperature plasma assisted chemical vapor generation system with an atomic fluorescence spectrometer. Responses of As, Te, Sb and Se were linear in the range of 0.5-20μg mL(-1). The RSDs of As, Te, Sb and Se in the present method were less than 4.1% and the absolute detection limits for As, Te, Sb and Se were 0.6ng, 1.0ng, 1.4ng and 1.2ng, respectively. Furthermore, four arsenic species were determined after HPLC separation. The method is green and simple compared with hydride generation with tetrahydroborate and the most attractive characteristic is micro-sampling. In principle, the method offers potential advantages of miniaturization, less consumption and ease of automation.