Determination of trace bismuth by solid phase extraction and anodic stripping voltammetry in nonaqueous media

The voltammetric characteristics of Bi(III) oxinate at the mercury electrode in chloroform are investigated. Anodic stripping voltammetry (ASV) for the determination of trace bismuth was developed in chloroform, using the differential pulse technique to strip the amalgamated bismuth from hanging mercury drop electrode (HMDE). The experimental variables such as scan rate of electrode potential, deposition potential, deposition time and stirring speed were optimized. The linear range of calibration graph and the detection limit were 5×10-8 to 5×10= 6 and 3.5×10-9M for Bi(III), respectively. Preceded by a preconcentration stage by solid phase extraction using octylsilane (RP-8) cartridge and subsequent elution by chloroform, the detection limit of the method is improved in 4.5×10-10M. The suitability of the proposed method for determination of trace bismuth in real sample was established by the analysis of a metallic aluminum sample.