| Abstract: | Ascorbate oxidase from zucchini squash was immobilized onto CH-Sepharose via carbodiimide. The properties of the immobilized enzyme were found to be similar to those of the free ascorbate oxidase. The immobilized enzyme was utilized in a flow-through system equipped with a polarographic detector which monitors the oxygen depletion due to the reaction ascorbic acid + 1/2 O2----dehydroascorbic acid + H2O. This method, the response of which is linear between 3 X 10(-7) and 5 X 10(-4) M ascorbate, was utilized to measure the ascorbic acid in biological samples such as human plasma and fruit juices at a rate of about 60 determinations every hour with a standard deviation lower than 5%. |
