Biosensori elettrochimici di tipo amperometrico di potenziale interesse nella caratterizzazione di produzioni agroalimentari

In this study, some thiophene-based conducting polymers, deposited on a WE surface, are used as a matrix for the entrapment of enzymes as glucose oxidase (GOx) for glucose detection and tyrosinase (Tyr) for cathecol detection. GOx was covalently immobilized on polythiophene film by cross-linking with 1-Cyclohexyl-3-(2-morpholinoethyl)-carbodiimide metho-p-toluenesulfonate (CMC) (1) as condensing agent or albumin sierum bovine and glutaraldehyde (GA). Tyr was immobilized on the polymeric film by cross-linking with GA, or covalently by activation of carboxylic groups that are present in the some polythiophene structure using a solution of EDC/NHS (0.4/0.1 M). Amperometric response of biosensors at varying the concentration of analyte was recorded in a three-electrode cell containing phosphate buffer (pH 7). For GOx biosensor, a redox mediator (p-benzoquinone), was for electronic-excange. Biosensors performance have been checked in standard samples and for GOx biosensors in real samples.Another bi-enzymatic biosensor based on Aldehyde dehydrogenase (β-NAD+dependent) and Diaphorase for 5-hydroxymethyl-2-furaldheyde (HMF) detection was studied (2). Polypyrrole was used as matrix for the enzymes immobilization by entrapment or cross-linking with BSA and GA. Amperometric response of biosensor at varying the concentration of HMF was recorded in a three-electrode cell containing phosphate buffer pH 7,5 and [Fe(CN)6]3-as redox mediator.1. Liu C. et al. Europ. Polym. J. 2007, Vol. 43, p. 3264-3276.2. Lomillo M. A. et al. Electroanal. 2006, Vol. 18, p. 2435-2440.