Liquid Spray Dielectric Barrier Discharge Induced Plasma–Chemical Vapor Generation for the Determination of Lead by ICPMS

In the present study, a novel and sensitive liquid spray dielectric barrier discharge induced plasma-chemical vapor generation technique (LSDBD-CVG) is developed for the determination of lead concentration by inductively coupled plasma mass spectrometry (ICPMS). The dissolved Pb2+ is readily converted to volatile species by LSDBD plasma induced chemical processes in the presence of 5% (v/v) formic acid in a supporting electrolyte (HCl, 0.01 mol L-1). In this LSDBD approach, the sample solution is converted to aerosol and simultaneously mixed with the DBD plasma generated at the nozzle of a pneumatic nebulizer, which greatly facilitates Pb vapor generation because of the enhanced interaction of sprayed analytes and the plasma. Optimal conditions for LSDBD-CVG were identified, and the interference effects from other metal ions were assessed. Under optimized conditions, the detection limit of Pb was found to be 0.003 μg L-1. The repeatability, expressed as the relative standard deviation (RSD) of the peak height, for the five replicate measurements of 0.03 and 1 μg L-1 lead standard, were 2.1% and 1.7%, respectively. Compared with other vapor generation methods, this new LSDBD-CVG offers several advantages including no requirement of unstable reagents, fast response, and easy coupling with flow injection, along with high tolerance for coexisting ions. The accuracy of the proposed method is demonstrated by successful analysis of Pb in reference material of stream sediment (GBW07311), soil (GBW07403), basalt (BCR-2), and simulated water sample (GBW08601). The proposed LSDBD-CVG extends the scope of elements accessible by plasma-CVG and provides an alternative efficient green approach for the vapor generation of Pb.