Effects of nonionic surfactants on electrochemical behavior of ubiquinone and menaquinone incorporated in a carbon paste electrode

A carbon paste electrode, in which the carbon particles were coated with a thin layer of a nonionic surfactant (NIS), was constructed with a pasting liquid containing ubiquinone (UQ) or menaquinone (MQ). It has revealed that the layer acts not only as a diffusion barrier but also as a matrix for the redox reaction of quinones at electrode surface, and its effects on the electrochemical behavior of quinones depend on both the physico-chemical structure of a surfactant and the kind of quinones. Further, such a modification was applied to the preparation of an enzyme electrode in which the quinone molecule act as a redox mediator and the influences on the sensitivity of the glucose biosensor was demonstrated.