苄基功能化离子液体对有机磷和苯环化合物的分散液-液微萃取性能研究

Benzyl Functionalized Ionic Liquid as New Extraction Solvent of Dispersive Liquid-liquid Microextraction for Enrichment of Organophosphorus Pesticides and Aromatic Compounds

以苄基功能化的离子液体1-苄基-3-甲基咪唑双三氟甲烷磺酰亚胺（1-Benzyl-3-methylimidazolium bis[（trifluoromethyl）sulfonyl]imide,[Be MIM][Tf2N]）作为分散液-液微萃取的萃取剂,与高效液相色谱联用,用于环境水样中5种有机磷农药（辛硫磷、杀螟松、毒死蜱、甲拌磷和对硫磷）以及2种苯环化合物（氯化萘和蒽）的萃取与富集。并与其它离子液体（[OMIM][Tf2N]）以及普通有机溶剂（CCl4和C2Cl4）的萃取效能进行了对比。萃取优化条件为：40μL[Be MIM][Tf2N]作为萃取剂,1 m L甲醇作为分散剂,离心时间5 min,样品溶液中不添加盐。在优化的条件下,本方法的线性关系良好（R2=0.9994~0.9998）;对10,40和100μg/L不同添加浓度重复测定5次的日内和日间RSD分别为1.1%~4.3%和0.8%~4.8%,LOD为0.01~1.0μg/L（S/N=3）。将本方法用于3种实际水样中目标分析物的测定,加标回收率和RSD分别为82.7%~118.3%和0.7%~5.6%。由于在咪唑环上引入了苄基基团,[Be MIM][Tf2N]与目标分析物之间除存在疏水作用外,还存在π-π作用,故对目标物的萃取效率明显提高,富集倍数和回收率分别高达339和81.4%。测定了分析物在[Be MIM][Tf2N]-DLLME体系中的分配系数,对萃取机制进行初步探讨。

A benzyl functionalized ionic liquid, 1-benzyl-3-methylimidazolium bis [（ trifluoromethyl ） sulfonyl]imide （[BeMIM][Tf2 N]）, was synthesized and characterized as an extraction solvent of dispersive liquid-liquid microextraction （ DLLME） for enrichment and determination of 5 organophosphorus pesticides （phoxim, fenitrothion, chlorpyrifos, phorate and parathion） and 2 aromatic compounds （chloronaphthalene and anthracene） from environmental water samples by high-performance liquid chromatography （ HPLC）.＆amp;nbsp;[BeMIM] [ Tf2 N] had higher extraction efficiency than 1-octyl-3-methylimidazolium bis [（ trifluoromethyl） sulfonyl]imide and common organic solvents such as CCl4 and C2 Cl4 . The extraction was performed using 40 μL of [BeMIM][Tf2N] and 1 mL of methanol as extraction solvent and dispersive solvent respectively with centrifugal time of 5 min. Under the optimal conditions, the method proposed here provided a good linearity for all analytes with correlation coefficients between 0. 9994 and 0. 9998. The repeatability values, described as intra-day and inter-day relative standard deviations （RSDs） of five replicate experiments at three different concentrations of 10, 40 and 100 μg / L, were 1. 1% -4. 3% and 0. 8% -4. 8% , respectively. The limits of detection （LOD） were 0. 01 μg / L-1. 0 μg / L at a signal-to-noise ratio （S / N） of 3. This developed method was convenient and speedy, and could be employed to detect the analytes in three real environmental water samples with satisfactory relative recovery of 82. 7% -118. 3% and RSD of 0. 7% -5. 6% . Introduction of benzyl group into the imidazolium could obviously enhance the extraction efficiecny for analytes due to the π-πinteraction between [BeMIM] [ Tf2 N] and analytes. [ BeMIM] [ Tf2 N] was a satisfactory extraction solvent with a high enrichment factor of 339 and extraction efficiency of 81. 4% . Partition coefficients of all analytes in [BeMIM][Tf2 N]-DLLME system were determined and the extraction mechanism was discussed.