Chailapakul O, Amatatongchai M, Wilairat P, Grudpan K, Nacapricha D
Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand.
Talanta. 2004 Dec 15;64(5):1253-8. doi: 10.1016/j.talanta.2004.04.023.
The electrochemical determination of iodide was studied at boron-doped diamond thin film electrodes (BDD) using cyclic voltammetry (CV) and flow-injection (FI) analysis, with amperometric detection. Cyclic voltammetry of iodide was conducted in a phosphate buffer pH 5. Experiments were performed using glassy carbon (GC) electrode as a comparison. Well-defined oxidation waves of the quasi-reversible cyclic voltammograms were observed at both electrodes. Voltammetric signal-to-background ratios (S/B) were comparable. However, the GC electrode gives much greater in the background current as usual. The potential sweep rate dependence exhibited that the peak current of iodide oxidation at 1mM varied linearly (r(2) = 0.998) with the square root of the scan rate, from 0.01 to 0.30Vs(-1). This result indicates that the reaction is a diffusion-controlled process with negligible adsorption on BDD surface, at this iodide concentration. Results of the flow-injection analysis show a highly reproducible amperometric response. The linear working range was observed up to 200muM (r(2) = 0.999). The detection limit, as low as 0.01muM (3sigma of blank), was obtained. This method was successfully applied for quantification of iodide contents in nuclear emergency tablets.
采用循环伏安法（CV）和流动注射（FI）分析法并结合安培检测，在掺硼金刚石薄膜电极（BDD）上研究了碘化物的电化学测定。碘化物的循环伏安法在pH 5的磷酸盐缓冲液中进行。使用玻碳（GC）电极作为对照进行实验。在两个电极上均观察到了准可逆循环伏安图中明确的氧化波。伏安信号与背景比（S/B）相当。然而，GC电极的背景电流通常要大得多。电位扫描速率依赖性表明，在1mM时碘化物氧化的峰值电流与扫描速率的平方根在0.01至0.30Vs（-1）范围内呈线性变化（r（2）= 0.998）。该结果表明，在此碘化物浓度下，反应是一个扩散控制过程，在BDD表面的吸附可忽略不计。流动注射分析结果显示出高度可重复的安培响应。观察到线性工作范围高达200μM（r（2）= 0.999）。获得了低至0.01μM（空白的3σ）的检测限。该方法成功应用于核应急片剂中碘化物含量的定量分析。
