An Enzymatic Clay-Modified Electrode for Aerobic Glucose Monitoring with Dopamine as Mediator

Abstract

Considering the unique adsorption and regeneration properties of dopamine, glucose oxidase, and nontronite, a glucose sensor was constructed by immobilizing glucose oxidase and nontronite clay coating on a glassy carbon electode with dopamine as mediator. The response of the glucose sensor was determined by measuring the cyclic voltammetric oxidation peak current values of dopamine under aerobic solution conditions. The effects of the amount of enzyme immobilized, the operating pH, and the common interferences on the response of the glucose sensor were studied. The detection limit was 7.4 µM (S/N ) 3), with a linear range extending to about 10 mM, giving a dynamic range of about 3 orders of magnitude for 0.8 mM dopamine. When stored in pH 7 phosphate buffer at 4 °C, the sensor shows almost no change in performance after operating for 45 days.

Peer Reviewed: The Prospects of Clay Mineral Electrodes

“…The calculated detection limit is 5 µM, and the current sensitivity for glucose is 59.6 µA/(mM cm 2 ), with 3 orders of magnitude dynamic detection range up to ~10 mM (15). These nontronite systems, in accordance with the physicochemical characteristics discussed earlier, also possess better sensitivity than the montmorillonite-clay modified GOx systems based on Ru(NH 3 ) 6…”

Clay Modified Electrodes: Present Applications and Prospects

“…This sandwich configuration of the enzyme immobilization ensured great stability of the sensor and eliminated interference from ascorbic and uric acid present in biological fluids. Another interesting glucose sensor based on the adsorption and the regeneration properties of dopamine, glucose oxidase and nontronite was developed, too [120]. The method of the enzyme immobilization ensured the great stability and the anti-interference properties of the biosensor.…”

Electrocatalytic Oxidation of Dopamine and Ascorbic Acid on Carbon Paste Electrode Modified with Nanosized Cobalt Phthalocyanine Particles: Simultaneous Determination in the Presence of CTAB

“…Chemically modified electrodes by covering the electrode surface with an appropriate permselective coating such as Nafion [3] were widely used to determine DA, which is known to repel AA at physiological pH. And inorganic ionomers, such as zeolites [4] and nontronit clays [5], were also studied. Second, some methods of simultaneous determination of DA and AA have been investigated for over past years.…”