Atomic absorption spectrometric determination of lead in gasolines by generation of its covalent hydride

Abstract

This paper describes a method for the atomic absorption spectrometric determination of lead in gasolines by hydride generation directly in the sample diluted with N,N-dimethylformamide (DMF) and with the addition of NaBH₄ solution in a 2%m/V DMF solution. The determination is carried out with an electrothermal atomiser (an electrically heated quartz tube). The gasolines were initially standardised using two ASTM methods, and the values for concentrations of lead obtained were used for studying the best conditions for the hydride generation and the calibration. Beer's law is obeyed for up to 0.40 µg of lead, and the sensitivity obtained is ca. 10 ng ml^–1. The method has been applied to the determination of lead in commercial gasolines, with good accuracy and precision.