Biosensing methods for xanthine determination: a review.

Xanthine (3,7-dihydro-purine-2,6-dione) is generated from guanine by guanine deaminase and hypoxanthine by xanthine oxidase (XOD). The determination of xanthine in meat indicates its freshness, while its level in serum/urine provides valuable information about diagnosis and medical management of certain metabolic disorders such as xanthinuria, hyperurecemia, gout and renal failure. Although chromatographic methods such a HPLC, capillary electrophoresis and mass spectrometry are available for quantification of xanthine in biological materials, these suffer from certain limitations such as complexity, time consuming sample preparation and requirement of expensive apparatus and trained persons to operate. Immobilized XOD based biosensors have emerged as simple, rapid, sensitive and economic tools for determination of xanthine in food industries and clinical diagnosis. This review article describes the various immobilization methods of XOD and different matrices used for construction of xanthine biosensors, their classification, analytical performance and applications along with their merits and demerits. The future perspectives for improvement of present xanthine biosensors are also discussed.