Inpota Prawpan, Strzelak Kamil, Koncki Robert, Sripumkhai Wisaroot, Jeamsaksiri Wutthinan, Ratanawimarnwong Nuanlaor, Wilairat Prapin, Choengchan Nathawut, Chantiwas Rattikan, Nacapricha Duangjai
Center of Excellence for Innovation in Chemistry and Department of Chemistry, Faculty of Science, Mahidol University.
Flow Innovation Research for Science and Technology Laboratories (FIRST Labs.).
Anal Sci. 2018;34(2):161-167. doi: 10.2116/analsci.34.161.
A microfluidic method with front-face fluorometric detection was developed for the determination of total inorganic iodine in drinking water. A polydimethylsiloxane (PDMS) microfluidic device was employed in conjunction with the Sandell-Kolthoff reaction, in which iodide catalyzed the redox reaction between Ce(IV) and As(III). Direct alignment of an optical fiber attached to a spectrofluorometer was used as a convenient detector for remote front-face fluorometric detection. Trace inorganic iodine (IO and I) present naturally in drinking water was measured by on-line conversion of iodate to iodide for determination of total inorganic iodine. On-line conversion efficiency of iodate to iodide using the microfluidic device was investigated. Excellent conversion efficiency of 93 - 103% (%RSD = 1.6 - 11%) was obtained. Inorganic iodine concentrations in drinking water samples were measured, and the results obtained were in good agreement with those obtained by an ICP-MS method. Spiked sample recoveries were in the range of 86%(±5) - 128%(±8) (n = 12). Interference of various anions and cations were investigated with tolerance limit concentrations ranging from 10 to 2.5 M depending on the type of ions. The developed method is simple and convenient, and it is a green method for iodine analysis, as it greatly reduces the amount of toxic reagent consumed with reagent volumes in the microfluidic scale.
开发了一种采用正面荧光检测的微流控方法用于测定饮用水中的总无机碘。将聚二甲基硅氧烷（PDMS）微流控装置与桑德尔-科尔托夫反应结合使用，其中碘化物催化铈（IV）和砷（III）之间的氧化还原反应。将连接到荧光分光光度计的光纤直接对准用作远程正面荧光检测的便捷检测器。通过将碘酸盐在线转化为碘化物来测定饮用水中天然存在的痕量无机碘（IO和I），以确定总无机碘。研究了使用微流控装置将碘酸盐在线转化为碘化物的效率。获得了93 - 103%的优异转化效率（%RSD = 1.6 - 11%）。测量了饮用水样品中的无机碘浓度，所得结果与通过电感耦合等离子体质谱法获得的结果高度一致。加标样品回收率在86%（±5） - 128%（±8）范围内（n = 12）。研究了各种阴离子和阳离子的干扰，其耐受极限浓度根据离子类型在10至2.5 M范围内。所开发的方法简单方便，是一种绿色的碘分析方法，因为它在微流控规模下大大减少了有毒试剂的消耗量。
