Département de chimie moléculaire

The detn. of xanthine has considerable importance in clin. and food quality control. Therefore, in this present work, the authors developed a novel xanthine biosensor based on immobilization of xanthine oxidase (XnOx) by attractive materials layered double hydroxides (LDHs). Amperometric detection of xanthine was evaluated by holding the modified electrode at 0.55 V (vs. SCE). Due to the special properties of LDHs, such as chem. inertia, mech. and thermal stability, anionic exchange ability, high porosity and swelling properties, XnOx/LDHs-modified electrode exhibited a developed anal. performance. The biosensor provided a linear response to xanthine over a concn. range of 1 × 10-6 M to 2 × 10-4 M with a sensitivity of 220 mA M-1 cm-2 and a detection limit of 1 × 10-7 M based on S/N = 3. In addn., the immobilized XnOx layers were characterized using at. force microscopy under both air atm. and liq. environment, which exhibited the interesting swelling phenomenon of LDHs. The investigation of inhibition of XnOx by allopurinol was carried out using this XnOx/LDHs-modified electrode. The exptl. results indicated that inhibitory effect could be achieved by allopurinol with a quasi-reversible competitive type. [on SciFinder(R)]