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: Disclosed is a method for determining the degree of freshness of such raw, frozen and processed perishable foodstuffs as meat, poultry and fish and an instrument therefor. The degree of freshness can be easily determined by the method of the present invention in shorter periods of time than by the conventional methods.The method of this invention comprises determining the amount of certain decomposition products of adenosine triphosphate such as hypoxanthine, inosine and inosinic acid by measuring the consumption of dissolved oxygen while each compound is subjected to action by certain enzymes, i.e., hypoxanthine by xanthine oxidase, inosine by nucleoside phosphorylase and inosinic acid by alkaline phosphatase, nucleoside phosphorylase and xanthine oxidase.

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 rotor having N and S poles is rotatively supported through bearings from the lower end of an electrode to be immersed in a water sample in which dissolved oxygen is measured. A rotor driving means is disposed adjacent to the rotor, the means generally comprising a magnet which is so constructed that the N and S poles thereof alternately approach the rotor. The rotor follows the rotation of the rotor driving means to rotate in and stir the water sample.