Heavy metals determination using various in situ bismuth film modified carbon-based electrodes

The proposed work deals with the utilization of three carbon-based electrode substrates such as boron-doped diamond, glassy carbon and carbon paste for the preparation of in situ bismuth film modified electrodes. Such modified electrodes were subsequently used for the differential pulse anodic stripping voltammetric determination of heavy metal cations (Zn²⁺, Cd²⁺ and Pb²⁺) individually and simultaneously using similar experimental conditions (0.1 mol l⁻¹ acetic buffer solution of pH 4.5 as supporting electrolyte with the addition of 0.1 mmol l⁻¹ Bi³⁺, deposition potential of −1.4 V and deposition time of 120 s). The results showed that the modification step mostly enhanced the deposition and stripping process of studied cations when compared to the bare electrode substrates. A boron-doped diamond electrode was selected as the substrate for modification and the procedure was applied to the real sample analysis including water sample (certified reference material) and wastewater sample. Using the standard addition method the concentrations of particular heavy metals were quantified and the determined values were in a good agreement with those obtained by the reference method — high resolution atomic absorption spectroscopy with electrothermal atomisation and continual radiation source. This fact highlights that the developed in situ bismuth film modified boron-doped diamond electrode is a suitable electrochemical sensor to be applied to routine analysis of water samples containing heavy metals.