Measurement of the oxidants-antioxidants balance in liquids

摘要

The present invention describes a chemical method that can determine the oxidant-antioxidant balance in biological samples and other materials. In the example of the application of the invention that is presented in the description of the invention section 3,3′,5,5′-Tetramethylbenzidine (TMB) and its cation that has a characteristic color are used as an oxidation-reduction target. However any other substance that can change its optical, fluorescence luminescence properties upon oxidation or reduction could be used in its place. The invention can be applied in any shape of vessel and on a stable matrix as a dipstick. The invention is based on two reactions one redox and one enzymatic that take place at the same time. In a redox reaction, e.g. TMB cation will be reduced by antioxidants; in the enzymatic reaction, intact TMB will be oxidized by peroxides. In the process of reduction, TMB cation will be decolourized; and in the process of oxidation, intact TMB will be converted to a colour cation. After a period of the time and adding HCl, the amount of TMB cation can be easily measured by spectrophotometry at 450 nm (reference wavelength 620 or 570 nm) both by macro- and micromethods (ELISA reader). The quantitative amount of TMB cation is representative of the oxidants-antioxidants balance in sample. This is achieved by comparing the optical absorbance of each sample with the absorbance of a series of standards that comprise the standard curve. The standard solutions can be constructed by mixing varying proportions (0-100%) of hydrogen peroxide (as a representative of the oxidants) with uric acid (as a representative of the antioxidants). However the admixture of any other oxidant-antioxidant may be used. The invention can be useful for the evaluation of the oxidant-antioxidant balance in biological samples (serum, plasma, urine etc.) especially for the evaluation of age related and metabolic disease such as diabetes. In addition the invention may be useful for the estimation of the success of antioxidant therapy.