Miniaturized Dielectric Barrier Discharge Atomizer In Atomic Fluorescence Spectrometry And Its Analytical Applications

Dielectric barrier discharge (DBD) generates a homogeneous micro-plasma in gaseous phase. DBD is a low-temperature plasma, and it contains a large number of chemically active free radicals and ions during the discharge process, which plays an important role in promoting redox reaction and decomposition of chemical molecules. Consequently, DBD can serve as an approach of atomization of volatile species. Moreover, DBD provides a potential application in the miniaturization of atomic spectrometric instruments attributed to its unique advantages, e.g., low temperature, low power consumption, small size. In this respect, DBD is a promising technique in the commercialization of miniature instrumentation, and thus it deserves to be thoroughly investigated.In the present work, a miniaturized coaxial cylinderical DBD atomizer made by quartz and ceramic tubes has been successfully embedded in the commercial AFS instrument to replace the original electrothermal quartz furnace atomizer. The developed DBD-AFS system is applied for the determination of trace cadmium and tellurium in environmental samples by cold vapor generation and hydride generation. This miniaturized DBD atomizer exhibits various advantages, such as ease of fabrication, low cost, low contamination, low interfering effect.With a sample volume of 1000 μL, a detection limit of 0.006 μg/L is achieved for cadmium in the DBD-AFS system, along with a RSD value of 3.0%(1 μg/L). As for tellurium, a detection limit of 0.04 μg/L is derived along with a RSD value of 1.8% (5 μg/L). The analytical performances of the present DBD-AFS system are comparable as those obtained by the commercial AFS instrument. The developed DBD-AFS system is applied for the determination of cadmium and tellurium in a few certified reference materials and real samples. The results showed that reasonable agreements are achieved between the certified and the obtained values, giving rise to satisfactory spiking recoveries. In addition, the present DBD-AFS system could also be applied for the determination of other common vapor forming elements, e.g., Hg, As, Se, Pb and Sb, giving rise to similar capability as those by the commercial AFS instrument furnished with electrothermal quartz furnace atomizer. The reliability and practical applicability of the DBD-AFS system have been further demonstrated by analyzing As, Se, and Pb in a series of real water samples.