Carbon paste electrode with covalently immobilized thionine for electrochemical sensing of hydrogen peroxide

[摘要] A water-soluble redox mediator, thionin was covalently immobilized to the functionalized graphite powder and a carbon paste electrode was fabricated from this modified graphite powder. The immobilization procedure proved to be effective in anchoring the thionin mediator in the graphite electrode setup without any leakage problem during the electrochemical studies. The covalent immobilization of the thionin mediator was studied with FT-IR and the electrochemical response of the thionin carbon paste electrode was optimized on varying the supporting electrolyte, pH and scan rate. The modified electrode exhibited well-defined electrocatalytic activity towards the reduction of H2O2at a lower potential of-0.266 V with good sensitivity. The developed amperometric sensor was efficient towards H2O2in the linear range from 2.46 × 10-5M to 4.76 × 10-3M, with a detection limit of 1.47 × 10-5M respectively. Important advantages of this sensor are its excellent electrochemical performance, simple fabrication, easy renewability, reproducible analytical results, acceptable accuracy and good operational and long-term stability.

[发布机构] Department of Chemistry, School of Advanced Sciences, VIT University, Vellore; 632 014, India^1;Department of Analytical Chemistry, University of Madras, Guindy Campus, Chennai; 600 025, India^2

[效力级别] 工业技术

[关键词] Carbon paste electrode;Covalent immobilization;Electrocatalytic activity;Electrochemical performance;Electrochemical response;Electrochemical sensing;Electrochemical studies;Supporting electrolyte