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Construction And Application Of The Novel Composite Platforms For Biosensors

Posted on:2010-11-28Degree:MasterType:Thesis
Country:ChinaCandidate:X Y JiangFull Text:PDF
GTID:2121360275989069Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
A biosensor is an analytical device which converts a biological response into an electrical signal using biologic materials or organism as the molecular recognition substances according to biochemistry and electrochemistry theory. Over the past decades, much attention has been paid to how to improve the performance of the biosensors. To this end, in this dissertation, two kinds of new composite biosensor platform have been constructed and explored for the fabrication of amperometric ethanol and glucose biosensors.The ethanol biosensor was fabricated based on Meldola's blue functionalized ordered mesoporous carbon (MB/OMC). The MB/OMC coated glassy carbon electrode (MB/OMC/GCE) was prepared by non-covalent adsorption of MB on the surface of an ordered mesoporous carbon coated GCE (OMC/GCE). Alcohol dehydrogenase (ADH) was then immobilized on the MB/OMC/GCE by cross-linking with glutaraldehyde for the construction of the ethanol biosensor. Under the operation potential of -0.1 V (vs. Ag/AgCl), the as prepared biosensor was highly selective for ethanol without suffering any interference from some common electroactive compounds and exhibited a wide linear range up to 10 mM with a lower detection limit of 19.1μM as well as a high sensitivity of 34.58 nA/mM. Moreover, the detection of real samples was also satisfied.The glucose biosensor, based on electropolymerization of glucose oxidase (GOD) on the platinum nanoparticles/ordered mesoporous carbon (Pt/OMC) composite modified gold electrode, is presented. The Au/Pt/OMC electrode exhibited excellent electrocatalytic activity and rapid response for the oxidation/reduction of H2O2 in the presence of the platinum nanoparticles compared with the Au/OMC electrode. As such, we improved the glucose biosensor which exhibited a lower detection limit of 0.05 mM as well as a high sensitivity of 0.38μA/mM. In addition, analytical parameters such as the effects of pH value, applied potential, electroactive interferents and the stability of the biosensor were also discussed. The values of the detection of real samples agreed well with those obstained with spectrophotometry.
Keywords/Search Tags:Biosensor, Ordered mesoporous carbon, Meldola's blue, Platinum nanoparticles, Alcohol dehydrogenase, Glucose oxidase
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