Electrochemical detection of carbohydrates at carbon-nanotube modified glassy-carbon electrodes

This communication reports on the catalytic oxidation of carbohydrates and the sensitive and stable fixed-potential (+0.45 V) amperometric carbohydrate response at glassy-carbon electrodes modified with single-wall carbon-nanotube (CNT) coatings. Variables affecting the electrocatalytic oxidation are assessed and optimized. The oxidation process starts around +0.25 V using a 0.1 M NaOH electrolyte solution. The amperometric response is extremely stable, with no loss in sensitivity over a continuous 2 h operation. The flow-injection response is characterized with a detection limit of 10 muM galactose and a relative standard deviation of 3.45% (n=20). Such attractive performance characteristics indicate great promise for monitoring sugars in chromatographic effluents. (C) 2004 Elsevier B.V. All rights reserved.