METHOD FOR METHIONINE DETERMINATION IN STANDARD TEST AQUEOUS SOLUTIONS VIA CYCLIC VOLTAMMETRY ON GRAPHITE ELECTRODE, MODIFIED WITH COLLOIDAL GOLD PARTICLES

摘要

FIELD: chemistry.;SUBSTANCE: method for methionine determination in standard test aqueous solutions by cyclic voltammetry on a graphite electrode, modified with colloidal gold particles includes graphite electrodes modification with colloidal gold particles of the gold sol (molar ratio of HAuCl₄:Na₃C₆H₅O₇:NaBH₄=1:15:5) for 300 sec at accumulation potential of -1.0 V, followed by recording of reverse peaks of methionine electric oxidation on the cathode curve at the potential sweep rate of 100 mV/s at the background of 0.1 M solutionof NaNO₃ in the potentials range of -1.0 V to 1.0 V. Methionine concentration is determined by the magnitude of the reverse maximum current-voltage curves in the potentials range of -0.20 V to 0.40 V relative to the saturated silver chloride electrode, by addition of qualified mixtures.;EFFECT: increased sensitivity of methionine determination.;3 dwg, 1 tbl, 2 ex