Beschreibung:
<jats:p>Multi-walled carbon nanotubes (MWNTs) were coated first with methylene blue (MB) by noncovalent adsorption and then by horseradish peroxidase (HRP) and glucose oxidase (GOD) by covalent-linking. The MB-MWNTs/GOD/HRP composites formed stable films on screen-printed electrodes (SPE). The electrochemical and electrocatalytic behaviors of the bienzyme modified SPE were studied using cyclic voltammetry (CV) and amperometry. Using the MB-MWNT/GOD/HRP composites, glucose could be calibrated by amperometry at −0.35 V vs. SCE. The optimized response (at pH 7.0) had a sensitivity of 2.4 mA.M−1 and a limit of detection (3×S/N) of 35 µM. Tests of the portable bienzyme sensor demonstrate its imperviousness to the effects of ascorbic acid, uric acid and p-acetaminophen, as well as its ability to measure glucose concentrations ranging from 0.25 to 2 mM.</jats:p>