Direct Determination of Trace Lead in Seawater by Inductively Coupled Plasma Mass Spectrometry After Photochemical Vapor Generation

摘要

A novel method is developed for the determination of lead in seawater samples using nickel assisted photochemical vapor generation (PVG) coupled with inductively coupled plasma mass spectrometry (ICP-MS). The severe matrix effect of seawater on the suppression of the lead signal was efficiently eliminated by using a mixture of 15 mu g g(-1) Ni2+ and 10% (v/v) formic acid as a photochemical reduction medium, making direct determination of lead in seawater samples feasible. A method detection limit of 0.003 mu g g(-1) based on external calibration was obtained, and the sampling frequency of 20 h(-1) was achieved with a 30-second sample loading time and a 1.25-mL sample consumption. The relative standard deviation of the measurement results was 3.7% (RSD, n=7) in seawater spiked with 1 mu g g(-1) Pb2+ solution. The proposed method was successfully applied for the analysis of one standard reference material (Seawater-QC3163) and three seawater samples (collected from Shanghai, Haikou, and Sanya, P.R. China) with satisfactory results.