Dielectric barrier discharge micro-plasma emission source for the determination of lead in water samples by tungsten coil electro-thermal vaporization

In this study, a fast and simple approach to directly determinate lead in water samples by a low power dielectric barrier discharge (DBD) excitation source was developed using tungsten coil electro-thermal vaporization (WC ETV) for liquid microsample introduction. A 20 mu L sample was dropped onto the WC, and then the sample went through the drying, pyrolysis, subsequently the analyte was vaporized and swept directly into the dielectric barrier discharge micro-plasma for emission, and the whole process took only 3 min. The effects of operating parameters such as plasma gas flow rate, plasma input voltage, pyrolysis current, vaporization current and interferences from concomitant elements were investigated. Under the optimal conditions, the limit of detection (LODs, 3 sigma) was calculated to be 7.7 mu g L-1. Repeatability, expressed as the relative standard deviation of the spectral peak height, was 4.6% (n=11) for 0.1 mg L-1 lead standard solution. The proposed method was successfully applied to the determinations of Pb in water samples. (C) 2014 Elsevier B.V. All rights reserved.