Microscale on-line production and determination of melic acid using flow injection analysis, immobilized fumrase and malate dehydrogenase with chemiluminescence detection

Microscale on-line production of L-malic acid from fumaric acid using on-line immobilized fumrase is developed. Fumaric acid is aspirated continuously through immobilized fumarase using a flow injection manifold. A simple and rapid flow injection chemiluminescence system based on an immobilized malate dehydrogenase, methylene blue and luminol system is developed to monitor the production of malic acid. The log-log calibration graph for malate is linear from 4.0 x 10(-6) to 8.0 x 10(-5) M. The detection limit (3 sigma) is 4.0 x 10(-6) M. The RSD of 5 replicate injections of 3.2 x 10(-5) M malate is 3%. The conversion yield of malic acid is 30-95% depending on the concentration of fumaric acid used. (C) 2001 Published by Elsevier Science B.V.