Room-temperature Chelate Vapor Generation of Lead Using Ammonium O,O-Diethyl Dithiophosphate as a Chelating Reagent and Determination by Atomic Fluorescence Spectrometry in Environmental Water Samples

A novel gas-liquid separator (GLS) system for chelate vapor generation (Che-VG) combined with AFS was developed for the determination of trace Pb. It was shown that Pb can form a volatile chelate by mixing of Pb with ammonium O,O-diethyldithiophosphate (DEDTP) in various aqueous solutions. Under the optimal conditions (frit pores of the GLS, 5 - 15 mu m; solution pH, 6.7; DEDTP concentration, 0.4%; flow rate of the two feed solutions in the on-line mode, 1.2 mL min(-1); and carrier gas flow rate, 150 mL min(-1)), the calibration curve was linear up to 100 ng mL(-1) Pb. The limit of detection (LOD) was 1.1 ng mL(-1). The relative standard deviation was 5.6% for eleven replicate determinations of 10 ng mL(-1) Pb. The efficiency of Che-VG was estimated to be 12%, and the volatile Pb species was preliminarily studied by ICP-OES. This method was applied to determine trace Pb in water samples.