Speciation of trimethyllead in rainwater by gas chromatography-mass spectrometry after ethylation with sodium tetraethylborate comparison with other alkylation methods

Abstract This paper describes an analytical procedure to determine Me 3 Pb + in aqueous solution. The method consists of ethylation of Me 3 Pb + with NaBEt 4 in the presence of a small volume of hexane, and keeping an excess of Pb 2+ . So, in only one step, the ethylation, the extraction and the concentration of the analyte are carried out. The organic extract is analyzed by GC-MS in the selected ion monitoring mode, using Me 4 Pb as the internal standard. The different variables which affect the process — pH, volume of hexane and NaBEt 4 concentration — are optimized. Possible degradation compounds as well as the number of interferences are compared to the buthylation method through Grignard reaction. The method is applied to the analysis of an artificial rainwater solution as part of an international interlaboratory exercise, and the results obtained are discussed and compared with that given by buthylation method.