Preparation and characterisation of a quinone-functionalised polythiophene film on a modified electrode. Application to the potentiometric determination of glutathione and cysteine concentrations

The new compound 3-((2,5-dimethoxyphenyl)ethynyl)thiophene has been synthesised by Sonogashira coupling. A modified electrode coated with a polythiophene film bearing a quinone moiety was obtained by electropolymerisation of the thienyl group followed by anodic oxidation of para-dimethoxyphenyl group. The cyclovoltammetric response resulting from the reaction of glutathione with the benzoquinone moiety was investigated. The responses of the modified electrode as a new potentiometric sensor of reduced thiols are proposed.

The addition of thiols on quinone moiety induces variation of the potential of the electrode.