离子色谱法测定饱和卤水中痕量碘离子

Determination of Trace Iodide in Saturated Brine Using Ion Chromatography

建立了一种在线样品预处理、脉冲安培检测饱和卤水中痕量I^-的离子色谱新方法。进样体积为50止，选用CryptandC1浓缩柱富集I^-，并用10mmol／L NaOH洗脱样品中的基体Cl^-。用0．5mmol／LNaOH将I^-从浓缩柱转移到保护柱柱端。用IonPac AS20阴离子交换柱，25mmol／L NaOH淋洗分离，结合脉冲安培银工作电极检测。I^-检出限为0．07μg／L（3倍基线噪音）；I^-在5～1000μg／L范围内具有良好的线性关系（r=0．9995）。50μg／L的I^-溶液连续进样9次，峰高相对标准偏差（RSD）为1．0％。

A new method was developed for the determination of iodide in saturated brine by ion chromatography with pulsed amperometric detection and in-line pretreatment. IonPac Cryptand C1 column was used to concentrate iodide from 50 μL sample volume, which was subsequently rinsed with 10 mmol/L NaOH to remove interfering chloride. The iodide was elute from the concentrator by 0. 5 mmol/L NaOH and on the head of the AG20 guard column. The separation of iodide was achieved on an IonPac AS20 column with 25 mmol/L NaOH as eluent. The detection limit of iodide was 0. 07 μg/L （50μL injection, signal-to-noise ratio of 3 ） and the linear range of the calibration curve of peak height vs analyte concentration was from 5.0 μg/L to 1000 μg/L. Relative standard deviations （RSD） of the peak height for 0. 05 mg/L iodide was 1.0% （n =9）.