engleski

Plant-tissue biosensor for determination of L-ascorbic acid in natural and pharmaceutical products

Detection of ascorbic acid has involved biological, chemical and chromatographic methods, where HPLC is the most extensively used one for the determination of vitamins in food. Electrochemical biosensors may also be used for the determination of ascorbic acid. The use of plant tissues provides numerous advantages for the fabrications of biosensors. However, response times are generally longer because the target substrate must diffuse through cell membrane before reaching biocatalist. A plant tissue biosensor based on enzyme kinetics of ascorbate-oxidase for L-ascorbic acid was developed. A mixture of crude extract of homogenized cucumber (Cucumis sativus) and gelatine was immobilized onto supporting nylon net and mounted over Clark oxygen electrode. A low-cost homemade Clark oxygen electrode was applied as transductor. Concentrations of L-ascorbic acid were amperometrically determined by plant-tissue biosensor and compared by voltammetry (DPV) using hanging mercury electrode. Under optimal operating conditions, sensor showed high sensitivity to ascorbic acid. The ability of prepared sensor to operate in real samples (fruit juices and pharmaceutical formulation was demonstrated. Concentrations of vitamin C obtained with these methods were compared with Officials Specifications. Our results show god agreement. Preparing of tissue biosensor is adequately fast and cheap procedure, therefore amperometry and voltammetry are suitable techniques for determination of vitamin C.

L-ascorbic acid; plant-tissue biosensor; amperometry; voltammetry

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