SIMULTANEOUS DETERMINATION OF MULTICOMPONENT IN FOOD BY AMPEROMETRIC FIA WITH IMMOBILIZED ENZYME REACTORS IN A PARALLEL CONFIGURATION

Abstract

A simultaneous determination system for food components with FIAenzyme reactor methodology has been developed. The main flow lines of the system are composed of plural independent lines and plural immobilized enzyme reactors set in a parallel configuration. Enzymes used were glucose oxidase for glucose, lactate oxidase for lactate, alcohol oxidase for ethanol, g-fructosidase, mutarotase and glucose oxidase for sucrose, fructose-5-dehydrogenase for fructose, sulfite oxidase for sulfite, and glycerol dehydrogenase for glycerol. First, simultaneous determination of lactate, glucose and ethanol in alcoholic beverages and serum was performed by monitoring hydrogen peroxide. Each corresponding oxidase of the substrate was immobilized on an Amino-Cellulofine support. Interferences of ascorbate and/or urate in a sample were completely eliminated by using ascorbate- and urate-eliminating reactors. Next, glucose, fructose and sucrose were determined simultaneously. Hydrogen peroxide (for glucose and sucrose) and hexacyanoferrate (II) (for fructose) were monitored. Sucrose determination was performed with a glucose-eliminating reactor which was set just before the sucrose reactor. Interference of ascorbate was also eliminated by an ascorbate-eliminating reactor. Finally, sulfite, glucose, glycerol and ethanol in white wine were determined simultaneously. For the glycerol determination, the NADH produced was monitored at +0.75 V vs. Ag/AgCl. For sulfite determination, a platinum electrode covered with dialysis membrane was used in order to diminish the interference of polyphenol compounds.