DETERMINATION OF CITRATE BY FIA USING IMMOBILIZED ENTEROBACTER-AEROGENES CELLS AND ENZYME THERMISTOR FLOW MICROCALORIMETER DETECTION/

Immobilized whole cells of Enterobacter aerogenes were used as citrate -sensing biocatalyst. The cells efficiently metabolized citrate and th e heat released enabled thermometric flow injection analysis (FIA) of citrate with a linear detection range between 0.2 and 6 mM. The immobi lized cells were tested for operational stability over 200 runs. Some possible solutions to the problem of dealing with saccharidic substrat es, such as glucose, fructose, and sucrose, which may be present with the citrate and interfere with the determination, are also discussed.