Nacapricha D, Sangkarn P, Karuwan C, Mantim T, Waiyawat W, Wilairat P, Cardwell T, McKelvie I D, Ratanawimarnwong N
Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand.
Talanta. 2007 Apr 30;72(2):626-33. doi: 10.1016/j.talanta.2006.11.033. Epub 2007 Jan 16.
This paper describes the use of a pervaporation (PV) technique in a flow injection (FI) system for selective improvement in iodide analysis. Iodide in the sample zone is oxidized to iodine, which permeates through a hydrophobic membrane. Detection of the diffused iodine is achieved using the chemiluminescent (CL) emission at 425nm that results from the reaction between iodine and luminol. The method was applied for the analysis of some pharmaceutical products, such as nuclear emergency tablets and multivitamin tablets. Ascorbic acid present in multivitamin samples interfered seriously with the analysis, and off-line sample treatment using anion exchange resin was employed to successfully remove ascorbic acid before the analysis. Ascorbic acid was flushed from the column using 0.4M sodium nitrate followed by elution of iodide with 2M sodium nitrate. The detection limit (3S.D.) of the system was 0.5mgl(-1), with reproducibility of 5.2% R.S.D. at 5mgl(-1). Sample throughput was determined as 30injectionsh(-1). There was good agreement between iodide concentrations from extracted samples determined using four different methods, i.e., PV-FI, gas diffusion-flow injection, potentiometry and ICP-MS. A comparison of the analytical features of the developed pervaporation system with these of the previously reported chemiluminescence gas diffusion-flow injection previously reported is also described.
本文描述了在流动注射（FI）系统中使用渗透蒸发（PV）技术来选择性改进碘化物分析。样品区中的碘化物被氧化成碘，碘透过疏水膜。通过碘与鲁米诺反应产生的425nm化学发光（CL）发射来检测扩散的碘。该方法用于分析一些药品，如核应急片剂和多种维生素片剂。多种维生素样品中存在的抗坏血酸严重干扰分析，因此在分析前采用阴离子交换树脂进行离线样品处理以成功去除抗坏血酸。用0.4M硝酸钠从柱中冲洗掉抗坏血酸，然后用2M硝酸钠洗脱碘化物。该系统的检测限（3S.D.）为0.5mg l⁻¹，在5mg l⁻¹时的重现性为5.2%R.S.D.。样品通量测定为30次进样 h⁻¹。使用四种不同方法（即PV-FI、气体扩散-流动注射、电位法和ICP-MS）测定的提取样品中的碘化物浓度之间有很好的一致性。还描述了所开发的渗透蒸发系统与先前报道的化学发光气体扩散-流动注射系统的分析特性比较。
