engleski

Activity of Enzyme Electrochemical sensors in System Water/Organic Solvents and their Application in Food Analysis

The activity of glucose biosensor based on glucose oxidase was investigated in the system water/organic solvent. Three methods of enzyme immobilization on the modified graphite electrode surface were investigated. Solid graphite electrode was modified with the layer of NiHCF, NiHCF-Ru or InHCF-Ru electrodeposited on the surface. Glucose oxidase has been immobilised on the surface of modified electrode by cross-linking with glutaraldehyde and bovine serum albumine, bonding in photopolimer and entrapment of enzyme in hydrogel structure. Enzyme amperometric biosensor prepared in this way were characterized with cyclic voltammetry and amperometry. Beside determinations of basic characterstic of biosensor, the influence of organic solvent(ethanol, methanol, isopropanol, acetonitrile and acetone) on amperometric response of biosensors were studied, too. Biosensors with NiHCF-Ru and InHCF-Ru modified graphite electrodes were used for glucose determinations in milk and dairy products, as well as in alcoholic beverages. All measurements were performed in electrochemical cell in water/organic solvents system.The results obtained were compared with the standard enzymatic spectrophometric reference method. It can be pointed out that addition of some organic solvents (ethanol, methanol and acetonitrile) up to 10 % mass fraction enhance the measured amperometric signal and enable the determination of gucose in hydrophobic samples which is of great importance for food industry.

biosensor; organic solvents; food analysis

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