HIGH-THROUGHPUT FLOW-INJECTION ANALYSIS OF GLUCOSE AND GLUTAMATE IN FOOD AND BIOLOGICAL SAMPLES BY USING ENZYME POLYION COMPLEX-BILAYER MEMBRANE-BASED ELECTRODES AS THE DETECTORS/

The concentration of glucose was determined by a combination of how in jection analysis (FIA) with amperometric enzyme sensor detection. The enzyme sensor was prepared by immobilizing glucose oxidase on an elect rode coated with a polyion complex layer consisting of poly-L-lysine a nd poly(4-styrenesulfonate). The inner, polyion complex layer was usef ul for preventing electrochemical interferents (e.g., L-ascorbic acid, uric acid and acetaminophen) from reaching the electrode surface, whi ch was effective for reducing the interferential responses upon the in jections of biological and food samples. The sensor-based system could be used for the determination of glucose from 10 mu M to 3 mM with th e sampling rate of 180 h(-1), and was stable for more than 2 months. A n FIA system for determining L-glutamic acid (3 mu M-0.5 mM) was also prepared by using an enzyme electrode based on a glutamate oxidase/pol yion complex-bilayer as the detector. (C) 1998 Elsevier Science S.A. A ll rights reserved.