Chemiluminescence Determination of Tiopronin by Flow Injection Analysis Based on Cerium(IV) Oxidation Sensitized by Quinine

A flow injection analysis method is proposed for the determination of tiopronin based upon the oxidation by cerium(IV) in dilute sulfuric acid medium and sensitized by quinine. With the peak height as a quantitative parameter applying optimum working conditions, tiopronin is determined over the 1–400 µM range (150 µl per injection, n = 10, r = 0.9994) with a detection limit of 0.34 µM and an RSD (n = 10) less than 2% at 20 and 50 µM. The proposed method, combining the advantages of speed and sensitivity, was applied to the routine determination of tiopronin in a pharmaceutical preparation.