A GLUCOSE SENSOR MADE OF AN ENZYMATIC CLAY-MODIFIED ELECTRODE AND METHYL VIOLOGEN MEDIATOR

A novel glucose sensor has been contrived by immobilizing glucose oxid ase between two nontronite clay coatings on glassy carbon electrode wi th methyl viologen as mediator. The sandwich configuration proved to b e very effective in the determination of glucose, The response of the glucose sensor was determined by measuring cyclic voltammetric peak cu rrent values under aerobic solution conditions. The effects of the amo unt of enzyme immobilized, the operating pH, and the common interferen ces on the response of the glucose sensor were studied. The detection limit was 5 mu M, with a linear range extending to about 6 mM, giving a dynamic range of over 3 orders of magnitude for 0.1 mM methylviologe n, When stored in pH 7 phosphate buffer at 4 degrees C, the sensor sho ws almost no change in performance after operating for at least 2 mont hs. A mechanism for the operation of the glucose sensor is also propos ed.