Carbon film electrodes for oxidase-based enzyme sensors in food analysis |
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Authors: | Luca S De Florescu M Ghica M E Lupu A Palleschi G Brett C M A Compagnone D |
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Institution: | a Dipartimento di Scienze e Tecnologie Chimiche, Università Tor Vergata, via della Ricerca Scientifica, 00133 Rome, Italy b Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal c Dipartimento di Scienze degli Alimenti, Università di Teramo, via C. Lerici 1, 64023 Mosciano S. Angelo, Italy |
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Abstract: | Carbon film resistor electrodes have been evaluated as transducers for the development of multiple oxidase-based enzyme electrode biosensors. The resistor electrodes were first modified with Prussian Blue (PB) and then covered by a layer of covalently immobilized enzyme. Electrochemical impedance spectroscopy was used to characterize the interfacial behaviour of the Prussian Blue modified and enzyme electrodes; the spectra demonstrated that the access of the substrates is essentially unaltered by application of the enzyme layer. These enzyme electrodes were used to detect the substrate of the oxidase (glucose, ethanol, lactate, glutamate) via reduction of hydrogen peroxide at +50 mV versus Ag/AgCl in the low micromolar range. Response times were 1-2 min. Finally, the glucose, ethanol and lactate electrochemical biosensors were used to analyse complex food matrices—must, wine and yoghurt. Data obtained by the single standard addition method were compared with a spectrophotometric reference method and showed good correlation, indicating that the electrodes are suitable for food analysis. |
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Keywords: | Oxidase enzymes Carbon film electrodes Prussian Blue mediator Food analysis Wine |
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