Carbon film electrodes for oxidase-based enzyme sensors in food analysis

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 +50mV versus Ag/AgCl in the low micromolar range. Response times were 1-2min. 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.

Amperometric and impedimetric characterization of a glutamate biosensor based on Nafion® and a methyl viologen modified glassy carbon electrode

“…Electrochemical impedance spectroscopy can be used to determine quantitative parameters of electrode processes as well as to provide a fingerprint of the interfacial region (De Luca et al, 2005;Yang et al, 2006;Zhao and Ju, 2006). EIS measurements were carried out in Ringer's solution at room temperature over a frequency range from 100 mHz to 100 kHz at a polarization potential of −0.65 V/SCE with a frequency modulation of 10 mV.…”

Electroactive Nanostructured Membranes (ENM): Synthesis and Electrochemical Properties of Redox Mediator‐Modified Gold Nanoparticles Using a Dendrimer Layer‐by‐Layer Approach

“…Deposition of iron hexacyanoferrates (FeHCF) was carried out using the method described in [24]. Figure 4a illustrates three consecutive cyclic voltammograms showing Prussian Blue (PB) modification of the electrode.…”

Poly(thionine)-carbon nanotube modified carbon film electrodes and application to the simultaneous determination of acetaminophen and dipyrone

“…CFE present similar properties to glassy carbon, such as excellent electrical and mechanical properties, wide potential range, chemical inertness, robustness and reproducible performance [28]. CFE are easy to prepare, inexpensive, disposable and small [29], which facilitates their incorporation in portable devices. The modified electrodes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy and then used for sensing acetaminophen (ACOP) and dipyrone by differential pulse voltammetry and fixed-potential amperometry.…”