FLOW-INJECTION METHOD FOR THE SIMULTANEOUS DETERMINATION OF D-GLUCOSE AND 3-HYDROXYBUTYRATE WITH CO-IMMOBILIZED ENZYME REACTORS AND A CHEMILUMINOMETER

The simultaneous determination of D-glucose and 3-hydroxybutyrate in a plasma and serum by a split-stream flow-injection method using two immobilized enzyme reactors is described. One reactor for the determination of D-glucose was packed with glucose dehydrogenase and NADH oxidase co-immobilized on poly(vinyl alcohol) beads; the other reactor for 3-hydroxybutyrate was packed with 3-hydroxybutyrate dehydrogenase and NADH oxidase co-immobilized on the beads. The hydrogen peroxide produced by the enzymatic reactions was detected by measuring the chemiluminescence emitted upon admiring with luminol and potassium hexacyanoferrate(III). For 3-hydroxybutyrate the calibration graph was linear over the range 1X10(-6)-5X10(-4) M; for D-glucose it was 1X10(-5)-1X10(-3) M. One assay could be completed within 6 min with satisfactory precision (<2.9% relative standard deviation).