APPROACH TO THE DETERMINATION OF LEAD BY VAPOR GENERATION ATOMIC-ABSORPTION SPECTROMETRY

A new method for the determination of lead by vapour generation atomic spectrometry is described. This is based upon continuous flow methodo logy and involves the derivatization of lead, in the presence of an ox idant, with sodium tetraethylborate to yield volatile tetraethyllead. Simplex optimization was applied to this system and to conventional hy dride 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 ab sorption spectrometry were observed. These are approximately 4-5 times better than the equivalent hydride system and superior to all reliabl e 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 generatio n systems were 0.62 and 0.07 ng cm(-3), respectively. The determinatio n of lead in a standard reference water (NIST SRM 1643c) is reported a nd 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)).