Institution: | a Departamento de Química Analítica, Facultad de Farmacia, Universidad de Alcalá, 28871-Alcalá de Henares., Madrid, Spain b Departament d'Enginyeria Química, Escola Tècnica Superior d'Enginyeria Química, Universitat Rovira i Virgili, Carretera de Salou, s/n. 43006-, Tarragona, Spain c Instituto de Catálisis y Petroleoquímica, CSIC, Campus Universidad Autónoma de Madrid, 28049-, Madrid, Spain |
Abstract: | A new mediated amperometric biosensor for fructose is described. The sensor is based on a commercially available D-fructose dehydrogenase. The enzyme is incorporated in a carbon paste matrix containing Os(bpy)2Cl2 as redox mediator that achieves electron transfer at 0·1 V (versus Ag/AgCl) with maximum apparent current densities of 1·2 mA/cm2. The dependence of the steady-state current on the loading of the mediator and the enzyme, other electrode construction parameters, the operating potential, the pH and the temperature was studied. In the steady-state mode the response current was directly proportional to D-fructose concentration from 0·2 to 20mM with a detection limit of 35 μM (signal-to-noise ratio, S/N, 3). In the flow injection analysis mode the response current was directly proportional to D-fructose concentration from 0·5 to 15 M with a detection limit of 115 μM (S/N 3). The sensor was used for the determination of fructose in food samples in a flow injection system and validated with a commercial enzyme kit. |