An Amperometric Biosensor for Xanthine Determination Prepared from Xanthine Oxidase Immobilized in Polypyrrole Film

Abstract

In order to prepare a biosensor for the determination of xanthine, electropolymerization of pyrrole on Pt surface was carried out with an electrochemical cell containing pyrrole, ferrocene (as a electron mediator) and tetrabutylamonium tetrafluoroborat in acetonitrile by cyclic voltammetry between 0.0 and 0.9V (vs SCE) at a scan rate of 50mV/s upon Pt electrode. Xanthine oxidase was immobilized by a glutaraldehyde/bovine serum albumin (BSA) crosslinking procedure on to polypyrrole film after the electropolymerization processes. The response of the biosensor against xanthine was measured after 3-4 min following the application of a constant potential of + 0.7 V (vs SCE). The resulting biosensor exhibits excellent electrocatalysis for the xanthine. The amperometric determination is based on the electrochemical detection of H202, which is generated in enzymatic reaction of xanthine. The effect of various experimental conditions was examined for the determination of the analytical performance. The sensor responds to xanthine with a detection limit of 1.0 x 10(-6)M. The response current increases linearly with xanthine concentration up to 4.0 x 10(-4) M. The sensor remains relatively stable for 45 days.

Mediated xanthine oxidase potentiometric biosensors for hypoxanthine based on ferrocene carboxylic acid modified electrode

“…The potentiometric response was linear from 5 to 20 lM with a correlation coefficient of 0.994. This is similar to that obtained by Aslan and Kilic (Arslan, Yas ßar, & Kiliç, 2006). The minimum detectable concentration of Hx is 4.5 lM.…”

Design of an amperometric xanthine biosensor based on a graphite transducer patterned with noble metal microparticles

“…For xanthine oxidase the following have been proven to successfully mediate the electron transfer process: colloidal gold [14], cobaltphthalocyanine and ferricyanide [15] and ferrocene [16]. Prussian blue was also suggested to be a mediator [14] in designing xanthine oxidase biosensors, however, it is questionable whether it mediates the transport of electrons between the enzyme active site and the electrode or simply catalyses the electrochemical reduction of enzymatically generated H 2 O 2 .…”

“…Prussian blue was also suggested to be a mediator [14] in designing xanthine oxidase biosensors, however, it is questionable whether it mediates the transport of electrons between the enzyme active site and the electrode or simply catalyses the electrochemical reduction of enzymatically generated H 2 O 2 . Recently, the immobilization of xanthine oxidase in conductive organic polymers [16][17][18] has been exploited as a strategy for designing biosensors for xanthine monitoring.…”

Construction of an Electrochemical Xanthine Biosensor Based on Graphene/Cobalt Oxide Nanoparticles/Chitosan Composite for Fish Freshness Detection

“…The sensitivity of Nafion/XAO/Co3O4/CH/GR/GC (y=6.6x+0.03 R 2 ꞊0.9896) was found to be four times higher than Nafion/Co3O4/CH/GR/GC (y=1.7x+0.06 R 2 ꞊0.9896). Hence we can decide that the direct oxidation of xanthine has a contribution to biosensor response Lineweaver-Burk plot gave the apparent Michaelis-Menten constant (Km app ) value of 0.17 mM for immobilized enzyme, and this value is lower than those of a CuPtCl6/glassy carbon chemically modified electrode based xanthine biosensor (1.11 mM) [38] polypyrrole and ferrocene modified Pt electrode based xanthine biosensor (1.33 mM) [34], and a platinum electrodeposited polyvinylferrocenium perchlorate matrix modified Pt electrode based xanthine biosensor (3.45 mM) [39]. These results show that the current biosensor possesses higher affinity to xanthine compared with some of earlier biosensors.…”