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Voltammetric behaviour and amperometric sensing of hydrogen peroxide on a carbon paste electrode modified with ternary silver-copper sulphides containing intrinsic silver

The electrochemical behavior of three ternary mixed silver-copper sulphides toward hydrogen peroxide, at various pH values, is presented. Electrochemical characterization, performed using modified carbon paste electrode, revealed that the material that consists of Ag1.2CuS2, AgCuS and intrinsic metallic silver showed favorable electrochemical signal in the presence of H2O2, when measurements were performed at pH 5. According to the results of the additional electrochemical investigation, a novel mechanism involved in the genesis of electroanalytical signal is proposed. Obtained electronalytical signal, at operating potential of the 0 V (vs Ag/AgCl) toward H2O2, is proposed to proceeds according to the chemical-electrochemical (CE) mechanism without direct electrochemical reaction of H2O2 at the electrode. The amperometric response is linear in the 1-1000 μM H2O2 concentration range with detection limit of the 0.055 μM. Sensitivity is calculated to be 16.82 μA cm–2 mM–1. As optimum pH value, pH 5 was selected. In the presence of the uric acid, asorbic acid, oleic acid, citric acid and glucose no interference on the amperometric signal was observed. Being a robust and a simple electrode, with remarkable stability, repeatability and reproducibility, the optimized electrode was successfully tested for determination of the hydrogen peroxide in a commercially available contact lens solution.

Electrochemistry ; Sensors ; Metals ; Modified carbon electrode ; Reduction mechanism ; Contact lens solution

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