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Printed Electrochemical Glucose Biosensors And Its Application In Flow Injection Analysis

Posted on:2004-09-14Degree:MasterType:Thesis
Country:ChinaCandidate:J LiFull Text:PDF
GTID:2168360092491705Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
This thesis includes a review and two research sections. In the review, biosensors including the history, basic components and the fundamental principle are introduced. Catalytic electrochemical biosensors and electron-transfer mediators and immobilization strategies of the biocomponent involved in the biosensor methodology are reviewed, especially in the fabrication and applications of disposable catalytic electrochemical biosensors. The research section involves a disposable biamperometric capillary-fill device designed for glucose and a biamperometric flow injection analytical system proposed for glucose with screen-printed enzyme biosensor.In the first research section, a novel disposable capillary-fill device has been designed aiming at fabricating a biosensor that has some attractive features, such as easily producing in large scale, precisely sampling in clinic detection. A disposable biamperometric capillary-fill device for glucose is fabricated using thick-film technology and incorporating a polymer mediator and glucose oxidase. A simple electrode system consisting of two identical carbon screen-printed electrodes are used as a transducer. The reagent ink of glucose oxidase and [Os(bpy)2(PVP)10Cl]Cl is drop-coated on the biosensor substrate between the strips of the electrode. A microliter biamperometric capillary-fill device is constructed by adhesive of a glass cover and the biosensor substrate. A drop of test solution is automatically introduced to the microchannel by capillary action and then a water-soluble layer containing glucose oxidase is soluble and quickly dispersed throughout the volume of the microchannel. Under a voltage of 200 mV applied, the current response is directly proportional to the concentration of glucose in the solution. The disposable device for the analysis of glucose shows a linear response range from 0 to 15 mmol L-1 and is virtually insusceptible to interfering species such as 1 mmol L-1 ascorbic acid. When stored dry, especially at 4℃, the biosensor shows good stability over a month. The device designed is successfully applied to the determination of glucose in human serum. The device offers several advantages compared to the earlier device reported. First, the fabricating cost of the designed device is reduced and it is much easily fabricated because a simple electrode system consisting of two identicalcarbon screen-printed electrodes can be easily fabricated in one step and the price of the carbon ink is lower than that of both metal ink (palladium) and silver/silver chloride ink. Second, the selectivity and sensitivity of the assay can be improved because a relatively lower voltage is applied and an efficient polymer mediator having a high homogeneous rate constant is used. Third, compared with the capillary-fill device in our previous paper, it can be tested in less sample volume of ten microliters because the microchannel volume of two strips in present device is less than that of the previous device consisting four strips. Good reproducibility and storage stability and simple operation are obtained, which meet the prerequisites for disposable applications.In the second research section, a novel biamperometric screen-printed biosensor is designed in a flow injection analysis(FIA) for glucose. The proposed glucose biosensor is fabricated using a thick-film technique and immobilizing osmium polymer and glucose oxidase on carbon screen-printed electrodes by adsorption and cross-linking methods. The composition of the immobilization solution involving the enzyme, protein and link regent and the analytical conditions are optimized. The flow injection electrochemical system shows that a linear range for glucose is from 1 to 20 mmol L-1 and the detection limit is 0.3 mmol L-1 with an injection sample of fifty microliter, giving a throughout of about 40 samples per hour. The glucose biosensors retain their constant response after more than 50 injection and storage over a month. The biosensor is virtually insusceptible to interfering species such as 1 mmol L-1 ascor...
Keywords/Search Tags:Electrochemical biosensors, Biamperometry, Flow injection analysis, Glucose, Glucose oxidase
PDF Full Text Request
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