Electrochemical Study of Iodide in the Presence of 2-Thiobarbituric Acid-Catalytic Determination of 2-Thiobarbituric Acid

Electrochemical oxidation of iodide has been studied in the presence of 2-thioborbituric acid using cyclic voltammetry and controlled-potential coulometry. The results indicate that, the resulting iodine takes part in halogenations reaction with 2-thiobarbituric acid. In addition, the present data are indicative of the suitability of iodide as a quasi mediator for determination of 2-thiobarbituric acid in aqueous solutions. The reaction mechanism has been investigated and shown that, the quasi-catalytic peak currents are linearily dependent on the 2-thiobarnituric acid concentration. The method allows the determination of 2-thiobarbituric acid in range 4.0´10-5-1.010-3 mol/L. The relative standard deviation for 10 determinations of 1.0´10-4 mol/L 2-thiobarnituric acid is 2.2% and the detection limit of the method is 3.9´10-5 mol/L