Electrochemical detection of trace insulin at carbon-nanotube-modified electrodes |
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Authors: | Joseph Wang Mustafa Musameh |
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Institution: | Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003, USA |
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Abstract: | Carbon-nanotube (CNT)-modified glassy-carbon electrodes dramatically accelerate the electrooxidation of insulin to offer an attractive amperometric detection of this important hormone. Hydrodynamic voltammograms indicate a substantial lowering of the detection potential, with oxidation starting above +0.5 V (versus Ag/AgCl) and leveling off of the response above +0.7 V. The flow-injection amperometric response (at pH 7.4) is highly linear (to at least 1000 nM), reproducible (RSD=4.8%;n=30), and fast (peak width of 45 s). The high sensitivity (48 nA/μM) and moderate detection potential (+0.8 V) lead to a low detection limit of 14 nM. Such performance characteristics compare favorably with those of previously reported metal-oxide-modified electrodes for insulin, and indicate great promise for in vivo measurements of insulin release and for monitoring this hormone in chromatographic effluents. |
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Keywords: | Carbon nanotubes Insulin Electrocatalysis Flow-injection analysis |
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