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

A novel hypoxanthine (Hx) sensor is constructed using a sodium montmorillonite-methyl viologen carbon paste modified electrode. Xanthine oxidase (XO) is immobilized within a polyaniline film on the electrode surface by electropolymerization. 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 cyclic voltammetry. The response of the sensor is linear in the range of 1 μM–0.4 mM hypoxanthine and the minimum detectable level is 0.8 μM. The sensor can be applied to the determination of hypoxanthine in fish meat, and it is effective for eliminating interferences from coexisting substances in the samples.