FIELD: measurement technology. SUBSTANCE: invention relates to electrochemical analysis methods, particularly to analysis of solutions for determination of total antioxidant capacity. Invention relates to a method of determining antioxidant capacity of a solution using a potentiometric method, in which a phosphate buffer solution is prepared in advance, to which a system is added which contains an simultaneously oxidized and reduced form of metal in the complex compound K3[Fe(CN)6]/K4[Fe(CN)6], and evaluation of antioxidant capacity is carried out by change in oxidation-reduction potential of solution, measured between working platinum electrode and chloride-silver comparison electrode, recorded before and after introduction into initial solution of analyzed substance. From the total antioxidant capacity of the solution, a reducing and chelating reservoir is recovered, wherein the reducing capacity is pre-determined by potentiometric titration with an oxidized form of the reagent (K3[Fe(CN)6. Chelating reservoir is determined as the difference between the antioxidant capacity and the recovery capacity. EFFECT: obtaining reliable quantitative information on restoring and chelating properties of analyzed objects with antioxidant action, as well as high accuracy and reliability of obtained results.