Kinetic potentiometric determination of some thiols with iodide ion-sensitive electrode

This paper describes a kinetic potentiometric method for the determination of thiols (RSH): L-cysteine (cys), N-acetyl-L-cysteine (NAC), L-glutathione (glu), and D-penicillamine (pen). The proposed method is based on the reaction of formation the sparingly soluble salts, RSAg, between RSH and Ag+ ions. During this reaction potential-time curves were recorded by using an electrochemical cell with commercial iodide selective electrode. The rectilinear calibration graphs are obtained in the RSH concentration range from 1.0 x 10(-5) to 1.0 x 10(-3) M. The applicability of the proposed method was demonstrated by determination of chosen compounds in pharmaceutical dosage forms.