Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7149734 | Sensors and Actuators B: Chemical | 2012 | 8 Pages |
Abstract
In this study, peroxidase from alfalfa sprout extract (Medicago sativa) was immobilized on a gold electrode, using a solution of the zwitterionic surfactant 3-(1-tetradecyl-3-imidazolio)propanesulfonate (ImS3-14) containing well-dispersed gold nanoparticles. In the presence of hydrogen peroxide, the peroxidase enzyme catalyzes the oxidation of hydroquinone to o-quinone, which is electrochemically reduced at a potential of +0.09 V vs. Ag/AgCl. The hydroquinone biosensor exhibited excellent electrocatalytic activity under the optimized experimental conditions ([peroxidase] = 97 units mLâ1, [H2O2] = 7.4 Ã 10â5 M, pH 7.0, frequency of 100 Hz, pulse amplitude of 60 mV and scan increment of 4.0 mV). Peak current linearity was observed in the range of 6.96 Ã 10â7 to 8.54 Ã 10â6 M, and the detection limit was estimated to be 1.88 Ã 10â7 M. This biosensor demonstrated good repeatability and reproducibility with relative standard deviations of 3.6% and 6.5%, respectively, and an acceptable stability (at least 100 determinations). The method has been applied to the determination of hydroquinone in skin-brightening creams and the recoveries were 98.3-104.5%.
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Physical Sciences and Engineering
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Authors
Suellen Cadorin Fernandes, Franciane Dutra de Souza, Bruno Silveira de Souza, Faruk Nome, Iolanda Cruz Vieira,