Amperometric determination of bonded glucose with an MnO(2) and glucose oxidase bulk-modified screen-printed electrode using flow-injection analysis |
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Authors: | Turkusic Emir Kalcher Josef Kahrovic Emira Beyene Negussie W Moderegger Helmut Sofic Emin Begic Sabina Kalcher Kurt |
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Institution: | a Department of Chemistry, Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo, Bosnia and Herzegovina b Institut für Chemie-Theoretische Chemie, Karl-Franzens Universität-Graz, Strassoldogasse 10, A-8010 Graz, Austria c Institut für Chemie-Analytische Chemie, Karl-Franzens Universität-Graz, Universitätsplatz 1, A-8010 Graz, Austria |
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Abstract: | A screen-printed amperometric biosensor based on carbon ink double bulk-modified with MnO2 as a mediator and glucose oxidase as a biocomponent was investigated for its ability to serve as a detector for bonded glucose in different compounds, such as cellobiose, saccharose, (-)-4-nitrophenyl-β-d-glucopyranoside, as well as in beer samples by flow-injection analysis (FIA). The biosensor could be operated under physiological conditions (0.1 M phosphate buffer, pH 7.5) and exhibited good reproducibility and stability. Bonded glucose was released with glucosidase in solution, and the free glucose was detected with the modified screen-printed electrode (SPE). The release of glucose by the aid of glucosidase from cellobiose, saccharose and (-)-4-nitrophenyl-β-d-glucopyranoside in solution showed that stoichiometric quantities of free glucose could be monitored in all three cases.The linear range of the amperometric response of the biosensor in the FIA-mode flow rate 0.2 mL min−1, injection volume 0.25 mL, operation potential 0.48 V versus Ag/AgCl) extends from 11 to 13,900 μmol L−1 glucose in free form. The limit of detection (3σ) is 1 μmol L−1 glucose. A concentration of 100 μmol L−1 yields a relative standard deviation of approximately 7% with five injections. These values correspond to the same concentrations of bonded glucose supposed that it is liberated quantitatively (incubation for 2 h with glucosidase).Bonded glucose could be determined in beer samples using the same assay. The results corresponded very well with the reference procedure. |
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Keywords: | Bonded glucose Screen-printed electrode Manganese dioxide Glucose oxidase Glucosidase Flow-injection analyses |
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