A new amperometric bienzymatic biosensor based on biocomposites for the determination of gluconic acid in wines |
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| Authors: | Cetó Xavier Céspedes Francisco Capdevila Josefina del Valle Manel |
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| Institution: | a Sensors and Biosensors Group, Department of Chemistry, Universitat Autònoma de Barcelona, Edifici Cn, 08193 Bellaterra, Barcelona, Spain
b INCAVI - Station of Viticulture and Enology from Vilafranca, Pça. Àgora, 2, 08720 Vilafranca del Penedès, Barcelona, Spain |
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| Abstract: | A new amperometric bienzymatic biosensor for gluconic acid based on the coimmobilization of gluconokinase (EC 2.7.1.12) and phosphogluconate dehydrogenase (EC 1.1.1.44) by polysulfone membrane entrapment onto the surface of a graphite-epoxy composite is reported. This biosensor represents an alternative to gluconate dehydrogenase (EC 1.1.99.3) based methods, which is no longer commercially available. Measurements were done at an applied potential of +0.800 V, room temperature and phosphate buffer pH 7.50; obtaining a linear response range for gluconic acid extended from 7.0 × 10−6 to 2.5 × 10−4 M. Constructed biosensors showed good reproducibility for calibrations using different electrodes (RSD of 1.74%). Finally, biosensor was applied to real wine samples, and the results obtained were validated by comparison with those provided by a reference laboratory. Good correlation was found when the biosensor results were plotted vs. the reference values (slope = 1.03 ± 0.04, intercept = 0.01 ± 0.02, r2 = 0.995). |
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| Keywords: | Gluconic acid Amperometric biosensor Wine Bienzymatic Gluconokinase |
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