RESUMEN
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). [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.