Селективное вольтамперометрическое определение серусодержащих аминокислот в лекарственных средствах и витаминных комплексах на электроде, модифицированном пленкой из гексахлороплатината рутения

We have studied the electrocatalytic oxidation of sulfur-containing amino acids on an electrode with immobilized inorganic film of ruthenium(III) hexachloroplatinate (RuPtCl 6 ). It is established that the film of RuPtCl6 exhibits electrocatalytic activity during the oxidation of these amino acids and favors electrooxidation of cysteine, cystine and methionine at various potentials. Optimum conditions of RuPtCl 6 film electrodeposition onto the electrode surface for obtaining maximum catalytic effect during the oxidation of sulfur-containing amino acids are determined. Kinetic parameters of cysteine, cystine and methionine oxidation on this electrode are found. A method of selective voltammetric determination of sulfur-containing amino acids on the electrode modified by RuPtCl 6 film is developed. A linear dependence of the current on the concentration is observed from 5 to 5 mM for cysteine and cystine and from 0.5 to 5 mM for methionine. The proposed method for selective determination of sulfur-containing amino acids has been applied to the analysis of drugs and vitamin complexes.