Methylene‐green‐mediated carbon paste glucose biosensor

Abstract

An amperometric glucose bioelectrode based on the incorporation of methylene green (MG) within a glucose oxidase (GOD)-containing carbon paste is described. The electrode generates an anodic current in the range of 0.0-0.6V (vs. SCE). The optimum pH is 8.5. The apparent Michaelis constant for the Cali bration plot is 49.3 mM (at 0.5% MG and 5.0% GOD loadings). The electrode sensitivity is 18.1 PA/ mM cm2. The electrode is insensitive to paracetamol and ethanol. At 0.068 V the response to ascorbic acid (40 PM) accounts for 2.4% of that of the normal physiological glucose level in blood. The performance was optimized by systematically altering the electrode composition and electrode potential. The electrode was used to measure glucose in a serum sample and gave an acceptable correlation with the reference method Eksan-G results. Good stability was observed for storage in the dry state in the refrigerator.

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