Approach to the determination of lead by vapour generation atomic absorption spectrometry

Abstract

A new method for the determination of lead by vapour generation atomic spectrometry is described. This is based upon continuous flow methodology and involves the derivatization of lead, in the presence of an oxidant, with sodium tetraethylborate to yield volatile tetraethyllead. Simplex optimization was applied to this system and to conventional hydride generation. Characteristic concentrations of 0.36 ng cm^–3(Pb 283 nm) and 0.145 ng cm^–3(Pb 217 nm) for alkyl generation atomic absorption spectrometry were observed. These are approximately 4–5 times better than the equivalent hydride system and superior to all reliable literature values for characteristic concentrations of lead hydride generation atomic absorption spectrometry. Using the 283 nm lead line, limits of detection (3s) obtained for the hydride and alkyl generation systems were 0.62 and 0.07 ng cm^–3, respectively. The determination of lead in a standard reference water (NIST SRM 1643c) is reported and good agreement obtained between the certificate value (35.3 ± 0.9 ng cm^–3) and the experimentally derived value (34.8 ± 1.4 ng cm^–3).