INVESTIGATION OF A NOVEL CHRONOPOTENTIOMETRIC DETECTION METHOD USING A REDOX MEDIATOR MODIFIED CARBON ELECTRODE

Chemically modified electrodes are often employed as sensing element i n biosensors. In these cases, usually amperometric detection is employ ed. In this article chemically modified electrodes were prepared by ad sorbing a benzophenoxazine type redox mediator molecule on the surface of an electrochemically pre-treated glassy carbon electrode. A specia l measurement method for electrochemical signal generation was worked out with biosensors. In this method, in the initial period, a short (1 -10 s) controlled potential step is employed. After this the potential control is discontinued and the change of the electrode potential is followed in time with a zero current measuring apparatus. The rate of the potential change in a certain section of the relaxation curve is w ell correlated with the concentration of the species to be measured. I n the paper the basic principles of the technique as well as some prel iminary experimental results are summarised. In the experimental work NADH was used as a model compound.