Biosensor for detection of hypoxanthine based on xanthine oxidase immobilized on chemically modified carbon paste electrode

A novel hypoxanthine (Hx) sensor is constructed using a sodium montmorillon ite-methyl viologen carbon paste modified electrode. Xanthine oxidase (XO) is immobilized within a polyaniline film on the electrode surface by electr opolymerization. The hypoxanthine detection is based on the oxygen consumed due to the enzymatic reaction involving xanthine oxidase, Electrocatalytic reduction of oxygen and the response of the sensor are evaluated using cyc lic voltammetry. The response of the sensor is linear in the range of 1 mu M-0.4 mM hypoxanthine and the minimum detectable level is 0.8 mu M. The sen sor can be applied to the determination of hypoxanthine in fish meat, and i t is effective for eliminating interferences from coexisting substances in the samples. (C) 2000 Elsevier Science B.V. All rights reserved.