Article révisé par les pairs
Résumé : The performance of the recently developed batch injection analysis (BIA) technique was investigated with regard to the behaviour of enzyme-immobilized electrodes. Glucose oxidase and xanthine oxidase sensors were prepared by casting the enzyme-immobilized membranes on the electrode surface. The measurements are based on the amperometric detection of the product of the enzymatic reaction: hydrogen peroxide at + 650 mV vs. Ag/AfCl (GOx) or the reduced form of methylene blue at + 50 mV vs. Ag/AgCl (XOD). The enzyme glutamate dehydrogenase was incorporated in the carbon paste and the direct and phenaxine methosulphate-mediated detection of NADH was followed at the enzyme electrode. The major characteristics observed were simplicity of the equipment, a high sampling rate and limited consumption of the carrier, i.e., reagents such as the mediator and cofactor. The repeatability of the manual injection of the sample was shown to be the critical step in the BIA mode. A new BIA cell design, allowing semi-continuous solution draining, is reported.