Selective Determination of Glucose in Blood Plasma by Using an Amperometric Glucose Biosensor Based on Glucose Oxidase and a Chitosan/ Nafion/ IL/Ferrocene Composite Film

Abstract

<br /><span style="font-size: 9pt; mso-bidi-font-family: 'Times New Roman';">A kind of ferrocene mediated enzymatic biosensor was fabricated in order to the measurement of glucose as an important biological analyte. A homogenous mixture of ferrocene including Chitosan(CS), Nafion(Nf) and an imidazolium based ionic liquid, 1-butyl-3-methyl imidazoliumhexafluorophosphate, [BMIM]HF6PO4, was prepared. The mentioned mixture was cast on the surface of carbon ceramic electrode and an enzymatic layer was entrapped between two layers of this mixture in order to improving the mechanical stability of the biosensor. Cyclic voltammetry and chronoamperometry were used to investigate the analytical performance of the biosensor. Remarkable deduction of interfering signals produced by AA and UA was obtained by applying a constant potential (180mV) on the human plasma for a short period of time (100min). Values of practical parameters such as sensitivity (2.73 µA mM^-1cm^-2), linear range (95.23–1367.5 µM) and detection limit (48 µM) were obtained by the chronoamperometric studies. The apparent Michaels-Menten constant, Km (3.52 mM) was also calculated. In order to estimate the practical accuracy and precision of the enzymatic biosensor, a test of spiked glucose solution recovery in natural plasma was done.</span>