A Bismuth Film Electrode for Electrochemical Stripping Voltammetric Determination of Trace Heavy Metals in Food

A bismuth film electrode (BFE) was used as working electrode. Differential pulse anodic stripping voltammetry was applied to the determination of trace amounts of zinc,cadmium,and lead in food samples. Under conditions of enrichment potential of -1.4 V,enrichment time of 180 s,and bismuth film concentration of 150 μg·L-1,BFE exhibited good electrochemical response to oxidation and stripping of zinc,cadmium,and lead. Linear relationships between anodic stripping peak current and mass concentration of zinc(Ⅱ),cadmium(Ⅱ),and lead(Ⅱ) were in the same range of 5.0-40 μg·L-1,with detection limits (3S/N) of 0.80,0.65,0.58 μg·L-1 for zinc(Ⅱ),cadmium(Ⅱ),and lead(Ⅱ) respectively. Precision of the method was tested at concentrations of 25 μg·L-1 zinc(Ⅱ),cadmium(Ⅱ),and lead(Ⅱ) solution for 15 duplicates with BFE,values of RSD were 6.2%,5.1%,and 7.1%,respectively. The proposed method was applied to the determination of trace heavy metals in food,giving results in agreement with values obtained by GFAAS method.