Bi-enzyme reactor for electrochemical detection of low concentrations of uric acid and glucose.
An enzyme-based flow-injection amperometric analysis system (FIA) for monitoring of uric acid and glucose is described. The oxidase and peroxidase enzymes are physically coimmobilised in a sandwich-type reactor and ferrocene serves as a mediator. The assays are based on the measurement of a reduction current resulting from the enzymatic reactions, at a glassy carbon electrode held at 0.00 mV (vs. Ag/AgCl). The high selectivity (ascorbic acid did not interfere) is coupled to high sensitivity (a detection limit of 30 and 60 nmol/l for uric acid and glucose, respectively; signal/noise = 3) and good stability (the enzymes remained active for more than 6 weeks at 30 degrees C). The usefulness of the assay in clinical chemistry is illustrated by the measurement of human serum uric acid and glucose concentration. The results obtained were in fairly good agreement with those obtained using conventional hospital laboratory methods.
Department of Biological Psychiatry, University of Groningen, The Netherlands.
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Elekes
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Moscone
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Venema
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Korf
D001205:Ascorbic Acid / Q000737:chemistry; D015374:Biosensing Techniques; D002138:Calibration; D004563:Electrochemistry; D004800:Enzymes, Immobilized; D017022:Flow Injection Analysis; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase; D006735:Horseradish Peroxidase; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D014503:Urate Oxidase; D014527:Uric Acid / Q000032:analysis*
D004800:Enzymes, Immobilized; D014527:Uric Acid; D012834:Silver; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; D006735:Horseradish Peroxidase; D014503:Urate Oxidase; D005947:Glucose; D001205:Ascorbic Acid