Abstract: A new method of rapidly analyzing plural substances in the presence of biological catalyzers is disclosed. The method is practiced by way of the steps of injecting both pH buffer solution and specimen into a reaction cell, successively adding a plurality of enzymes to induce up-take reaction of dissolved oxygen, causing the plurality of substances to be subjected to selective oxidation in the stepwise manner, obtaining a stepdown curve of dissolved oxygen by automatically recording the oxidative process by means of a dissolved oxygen sensor, qualitatively determining each of the substances with reference to the kind of added enzymes and the order of their addition and quantitatively determining the same with reference to the extent of decrease in dissolved oxygen. Typically, oxidation of the substances is carried out by way of two or three or further more steps.

Abstract: A new method of rapidly analyzing plural substances in the presence of biological catalyzers is disclosed. The method is practiced by way of the steps of injecting both pH buffer solution and specimen into a reaction cell, successively adding a plurality of enzymes to induce uptake reaction of dissolved oxygen, causing the plurality of substances to be subjected to selective oxidation in the stepwise manner, obtaining a stepdown curve of dissolved oxygen by automatically recording the oxidative process by means of a dissolved oxygen sensor, qualitatively determining each of the substances with reference to the kind of added enzymes and the order of their addition and quantitatively determining the same with reference to the extent of decrease in dissolved oxygen. Typically, oxidation of the substances is carried out by way of two or three or further more steps.

Abstract: A rapid, accurate and simple method is disclosed for determining an index of freshness of fish and mollusks. The index of freshness is expressed as the ratio of the combined molar concentration of inosine and hypoxanthine to the total molar concentration of the decomposition products of adenosine triphosphate. Each concentration is determined electrochemically from the amount of hydrogen peroxide produced when a sample extract from fish or mollusks is subjected to the action of certain enzymes. The emzymes used for inosine and hypoxanthine concentration are nucleoside phosphorylase and xanthine oxidase and for the concentration of the decomposition products of adenosine triphosphate are alkaline phosphatase, adenylic acid kinase, AMP deaminase and adenosine deaminase in a crude extract obtained from calf intestine, nucleoside phosphorylase and xanthine oxidase. Sodium azide may be added to the sample extract to inhibit errors in measurement caused by the presence of catalase.