Extraction-atomic-absorption spectrophotometric determination of lead by hydride generation in non-aqueous media

Abstract

A method for lead hydride generation in a non-aqueous extraction phase is proposed. The lead hydride generation is carried out in an aliquot of lead pyrrolidine-1-carbodithioate extract in chloroform, by the addition of sodium tetrahydroborate(III) solution in dimethylformamide. Lead is determined by atomic-absorption spectrophotometry at 217.0 nm. The proposed method gives improved sensitivity and eliminates interferences, which is necessary because lead hydride generation in aqueous solution occurs in the presence of oxidants such as potassium dichromate or ammonium peroxydisulphate. The method was applied to the determination of lead in BCS standard steels and air particulates. Good accuracy and precision were obtained.