Electrodes with extremely high hydrogen overvoltages as substrate electrodes for stripping analysis based on bismuth-coated electrodes

Hydrogen evolution bothers stripping analysis significantly. Dioctyl phthalate-based carbon paste electrode exhibits extremely wide cathodic potential window. It is explored as a powerful substrate electrode to solve the problem of hydrogen evolution and further improve reproducibility for stripping analysis using bismuth-coated electrodes for the first time. It was successfully applied to the simultaneous determination of Zn2+, Cd2+, and Pb2+. Linear responses are obtained for Zn2+ in the range of 10–100 μg L−1 and for Pb2+ and Cd2+ in the range of 5–100 μg L−1. The detection limits for Zn2+, Cd2+, and Pb2+ are 0.1 μg L−1, 0.22 μg L−1 and 0.44 μg L−1, respectively. The method has been successfully applied to the determination of Zn2+, Cd2+, and Pb2+ in waste water samples. The detection strategy based on the combination of dioctyl phthalate-based carbon paste electrode and bismuth-coated electrodes holds great promise for stripping analysis.

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► Dioctyl phthalate-based CPE has extremely wide cathodic potential range.
► It has been used for bismuth-based stripping analysis for the first time.
► It can effectively avoid hydrogen evolution and improve reproducibility.
► It is suitable for detecting more active metals such as zinc.
► It is a powerful platform for bismuth-based electrochemical stripping analysis.