engleski

Rapid determination of glucose in food samples by an amperometric glucose-sensing electrode

Of the various methods available for determination of glucose in industrial food laboratories the most attractive are those based on amperometric enzyme electrodes. The combination of specific enzyme with sensitive electrochemical signal transduction yields enzyme electrodes, which provide simple, rapid and accurate determination of enzyme substrate. In this work cross-linking glutaraldehyde-BSA procedure for immobilization of enzyme was used. The enzyme was immobilized on the surface of a spectroscopically pure carbon electrode modified electrochemically with the layer of potassium nickel hexacyanoferrate (FeNiHCM). Glucose determinations were performed at – 50 mV vs. saturated calomel electrode Hg&frac12 ; ; Hg2Cl2&frac12 ; ; 3M KCl in 0.1 M KCl and phosphate buffer (pH = 5.5) as well as in mixed solvents (ethanol/water). The results obtained indicate that solid graphite electrode was successfully modified with the catalytic layer of FeNiHCM. Amperometric response of biosensor was pH and organic solvent volume fraction dependent. Linear concentration range from 0.1 mM to 1.00 mM glucose was obtained. In various samples of food such as yogurt (Bioaktiv LGG, Dukat), creams with chocolate (Mus, Dukat and Paradies Cream, Dr. Oetker) and strawberry flavour (Ledeni desert, Dr. Oetker) and whip cream powder (Šlag pjena, Aro) glucose was successfully determined.

glucose biosensor; amperometry; food analysis

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