Department of Applied Chemistry, China Agricultural University, Beijing, PR China.
J Sep Sci. 2011 Nov;34(22):3178-85. doi: 10.1002/jssc.201100577. Epub 2011 Oct 20.
A dispersive liquid-liquid microextraction (DLLME) method using in situ halide exchange reaction to form ionic liquid (IL) extraction phase was developed to determine four insecticides (i.e. methoxyfenozide, tetrachlorvinphos, thiamethoxam, and diafenthiuron) in water samples. The preconcentration procedure, followed by high-performance liquid chromatography and variable wavelength detectors (VWD), enabled the formation of the immiscible IL extraction phase; the insecticides were transferred into the IL phase simultaneously, which enhanced the efficiency and sufficiency, greatly shortening the operation time. The experimental parameters affecting the extraction efficiency including volume of extraction IL, extraction and centrifugation times, volume of the sample solution and exchanging reagent, and addition of organic solvent and salt were investigated and optimized. Under optimized conditions, the extractions yielded recoveries of the target analytes from 82 to 102%. The calibration curves were linear, and the correlation coefficient ranged from 0.9990 to 0.9999 under the concentration levels of 5-200 μg/L. The relative standard deviation (n=6) was 2.9-4.6%. The limits of detection (LODs) for the four insecticides were between 0.98 and 2.54 μg/L.
采用原位卤化物交换反应形成离子液体（IL）萃取相的分散液液微萃取（DLLME）方法，用于测定水样中的四种杀虫剂（甲氧虫酰肼、四氯虫酰胺、噻虫嗪和虫酰肼）。该预浓缩程序，结合高效液相色谱和可变波长检测器（VWD），形成了不混溶的 IL 萃取相；杀虫剂同时被转移到 IL 相中，这提高了效率和充分性，大大缩短了操作时间。考察并优化了影响萃取效率的实验参数，包括萃取 IL 的体积、萃取和离心时间、样品溶液和交换试剂的体积以及有机溶剂和盐的添加。在优化条件下，目标分析物的萃取回收率为 82-102%。在 5-200μg/L 的浓度水平下，校准曲线呈线性，相关系数范围为 0.9990-0.9999。相对标准偏差（n=6）为 2.9-4.6%。四种杀虫剂的检出限（LODs）在 0.98-2.54μg/L 之间。
