Application of SiO2-poly(dimethylsiloxane) hybrid material in the fabrication of amperometric biosensor |
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Authors: | Ho Wei-Jen Yuan Chiun-Jye Reiko Ohara |
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Institution: | Biodesign Institute, Departments of Chemical and Materials Engineering and Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287, USA |
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Abstract: | A highly sensitive adsorptive stripping voltammetric protocol for measuring trace beryllium, in which the preconcentration is achieved by adsorption of the beryllium-arsenazo-I complex at a preplated mercury-coated carbon-fiber electrode, is described. Optimal conditions were found to be a 0.05 M ammonium buffer (pH 9.7) containing 5 μM arsenazo-I, an accumulation potential of 0.0 V (versus Ag/AgCl) and a square-wave voltammetric scan. The new procedure obviates the need for renewable mercury-drop electrodes used in early stripping protocols for beryllium. A linear response is observed over the 10-60 μg l−1 concentration range (90 s accumulation), along with a detection limit of 0.25 μg l−1 beryllium (10 min accumulation). A 15-s electrochemical cleaning enables the same mercury film to be used for a prolonged operation. High stability is thus indicated from the reproducible response of a 100 μg l−1 beryllium solution (n = 60; RSD = 3.3%) over a 2.5-h operation. Applicability to a seawater sample is illustrated. The attractive behavior of the new sensor holds great promise for on-site environmental and industrial monitoring of beryllium. Preliminary data in this direction using mercury-coated screen-printed electrodes are encouraging. |
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Keywords: | Beryllium Mercury film electrode Arsenazo-I Adsorptive stripping voltammetry |
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