A Simple and Sensitive Method for the Detection of Trace Pb(II) and Cd(II) based on Nafion-coated Antimony Film Electrode

Nafion-coated antimony film electrode (NCAFE) was prepared in situ by simultaneously plated antimony with analytes, and applied to the determination of trace Pb(II) and Cd(II) in non-deaerated solutions by differential pulse anodic stripping voltammetry (DPASV). Various experimental parameters, which influenced the response of the NCAFE to those metals, were thoroughly optimized and discussed. The results indicated that the sensitivity and resistance to surfactants at the NCAFE were remarkably improved with relative to the antimony film electrode (AFE). In the presence of 5 mg.L (1) gelatin, the peak heights at the NCAFE showed 4-fold enhancement for Pb and a 9-fold enhancement for Cd over a bare AFE. Reproducibility of the sensor was satisfactory, and the relative standard deviations were 4.8% for 20 mu g.L (1) Pb and 3.2% for 25 mu g.L (1) Cd (n = 15) with preconcentration time of 180 s. The determination limits (S/N= 3) of this sensor were determined to be 0.15 mu g.L (1) for Pb and 0.30 mu g.L (1) for Cd with accumulation time of 300 s. The NCAFE was successfully applied to determining Pb(II) and Cd(II) in vegetable and water samples with satisfactory results.