A sensitive electrochemical analysis for cadmium and lead based on Nafion-Bismuth film in a water sample

Abstract

This study presents a simple, low-cost, sensitive and environmentally friendly approach for the simultaneous electrochemical determination of lead and cadmium based on a commercial screen-printed gold electrode (SPGE) with Nafion and an in situ bismuth film. The developed sensor was coated with a Nafion polymer to reduce the interference and enhance the stability and reproducibility of the gold working electrode and an in situ bismuth film to increase the sensitivity and achieve a low detection limit. Electrochemical properties were investigated using anodic stripping square voltammetry. The composite film was characterized using cyclic voltammetry, and scanning electron microscopy was carried out for the morphological characterization of the modified electrode. It was found that the prepared electrode has high sensitivity and good repeatability with a limit of detection below the Environmental Protection Agency limits (5 µg/L Cd and 10 µg/L Pb). The linear calibration curves for Pb(II) ranged from 20 ppb to 300 ppb, and for Cd(II), they ranged from 50 ppb to 300 ppb. The detection limits (S/N = 3) were estimated to be 3 ppb for Pb(II) and 4 ppb for Cd(II). This method was effectively applied in the application of river and tap water samples, and the results were compared with flame-atomic absorption spectroscopy analysis.