Simultaneous determination of L-malate and ethanol in wine by a sensor based on oxygen consumption including parallel configuration of enzyme columns

Abstract

The simultaneous determination system of L-malate and ethanol was developed by using two enzyme reactors in parallel and a single oxygen electrode. NADH formed in the reaction of malate dehydrogenase was regenerated to NAD with dissolved oxygen using vitamin K3 and diaphorase. Ethanol was determined by use of alcohol oxidase. When a sample solution was simultaneously injected to two reactors, a train of two peaks corresponding to ethanol and L-malate appeared in an FIA-gram. The peak current was linearly related to L-malate and ethanol concentration in the range 0.09~0.9 mM and 18~50mM, respectively. The present system was applicable to the determination of L-malate and ethanol in wine. © 1990, The Japan Society for Analytical Chemistry. All rights reserved.