Construction of an amperometric polyphenol biosensor based on PVA membrane
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ORIGINAL PAPER
Construction of an amperometric polyphenol biosensor based on PVA membrane Jagriti Narang • Sheetal Chawla • Nidhi Chauhan Monika Dahiya • Chandra Shekhar Pundir
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Received: 14 June 2012 / Accepted: 18 December 2012 / Published online: 4 January 2013 Ó Springer Science+Business Media New York 2013
Abstract A method is described for construction of an amperometric biosensor for determination of polyphenolic content using polyvinyl alcohol membrane bound polyphenol oxidase mounted on a gold coated Ag wire as a working electrode, a silver/silver chloride (Ag/AgCl) reference electrode and Pt wire as auxiliary electrode. The biosensor showed optimum response within 30 s, when operated at 30 °C. A linear relationship was obtained between L-DOPA concentration (0.5–20 lM) and current (lA). Limit of detection of the method was 0.5 lM. The biosensor measured polyphenols in tea leaves, alcoholic beverages and water. The enzyme electrode was used 280 times over 6 months, when stored at 4 °C. The biosensor is better than earlier membrane based biosensors in terms of detection limit (0.5 lM) and stability (6 months). Keywords Polyphenol Polyphenol oxidase PVA membrane Amperometric biosensor L-DOPA
Introduction Phenolic compounds, found in environment have deleterious effects on health and thus their determination is of great importance [1]. Many of these phenolic compounds have toxic effects on animals and plants of which they
J. Narang S. Chawla N. Chauhan M. Dahiya C. S. Pundir (&) Department of Biochemistry, M D University, Rohtak 124001, India e-mail: [email protected]
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easily penetrate the skin and membranes, determining a broad spectrum of genotoxic, mutagenic and hepatotoxic effects, also affecting the biocatalysed reaction rates in respiration and photosynthesis [2–4]. The determination of polyphenols is also important due to their biological importance as plant’s secondary metabolites, their ecological role in the antioxidant capacity, physiological effects, employment as markers in taxonomic studies and their properties to food quality control. Although various chromatographic techniques coupled with different detecting systems are available [5–13], these techniques do not allow continuous on-site monitoring, are expensive and time-consuming, and require skilled operators and preconcentration and extraction steps that increase the risk of sample loss. Immobilized polyphenol oxidase (PPO)/laccase based biosensors provide a fast and reliable alternative, due to their simplicity, specificity, fast response, reusability and cost effectiveness [14]. Among the various matrices used to immobilize PPO/laccase artificial membranes such as nylon membrane [14], eggshell membrane [15], polyvinylchloride (PVC) [16], nitrocellulose (NC) membrane [17], epoxy resin [18], polyethersulphone [19] have the advantages of their easy preparation without involving any equipment and regeneration of electrode over other matrices. Polyvinyl alcohol (PVA) membrane is elastic, non-fragile, has high mec
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