A gold electrode modified by a thin film of cationic kaolinite was used for the electrochemical detection of iodide in aqueous solution in the presence of thiosulfate. At gold electrode, iodide showed two electrochemical systems in the potential range explored (0.10 V to 0.85 V). The pH‐independent system was assigned to the redox couple I₂/I⁻ and the pH‐dependent one assigned to the redox couple HIO/ . For increased amount of thiosulfate the oxidation peak intensity of the first system increases sharply followed by the gradual decrease of the reduction peak, due to the chemical reaction between thiosulfate and oxidized iodide. The calibration curve in the presence of excess thiosulfate resulted in an increase of the sensitivity by a factor of 7. To improve this sensitivity, the bare gold electrode was coated by a thin film of an anionic exchanger kaolinite, obtained by grafting the ionic liquid (1‐(2‐hydroxyethyl)‐4‐(tert‐butyl) pyridinium chloride). Accumulation‐detection method yielded a spectacular increase of the oxidation peak current of iodide in the presence of thiosulfate ions. At optimized experimental conditions, a sensitivity of 2.45 μA.μM⁻¹ and a detection limit of 65 nM were obtained. The method was successfully applied for total iodine determination in povidone−iodine formulation.

中文翻译：

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硫代硫酸盐存在下阳离子高岭石修饰金电极上碘化物的催化检测

使用阳离子高岭石薄膜修饰的金电极用于在硫代硫酸盐存在下的水溶液中电化学检测碘化物。在金电极上，碘化物显示出在所探索的电位范围（0.10 V至0.85 V）中的两个电化学体系。在不依赖pH的系统被分配到氧化还原电对我₂ / I ^-和pH依赖性一个分配给所述氧化还原对HIO / 。由于硫代硫酸盐和氧化碘化物之间的化学反应，随着硫代硫酸盐量的增加，第一个系统的氧化峰强度急剧增加，然后还原峰逐渐降低。在过量硫代硫酸盐存在下的校准曲线导致灵敏度提高了7倍。为提高灵敏度，裸露的金电极涂有阴离子交换剂高岭石薄膜，该薄膜是通过将离子液体接枝而获得的（ 1-（2-羟乙基）-4-（叔丁基）氯化吡啶鎓）。积累检测方法在存在硫代硫酸根离子的情况下，使碘化物的氧化峰值电流显着增加。在优化的实验条件下，灵敏度为2.45μA.μM ^-1检测限为65 nM。该方法已成功应用于聚维酮-碘制剂中总碘的测定。