Preconcentration and determination of aromatic amines with temperature-controlled ionic liquid dispersive liquid phase microextraction in combination with high performance liquid chromatography

This paper reports a new method for the determination of aromatic amines with temperature-controlled ionic liquid dispersive liquid-phase microextraction in combination with HPLC and results of investigation of the influence of anions in ionic liquids on the extraction performance. In these experiments, 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]), 1-octyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide ([C8MIM][NTf2]), and 1-octyl-3-methylimidazolium tetrafluoroborate ([C8MIM][BF4]) were used as the extraction solvents for the investigation of the effect of anions in ionic liquids. Other parameters affecting the microextraction performance were also investigated. Under the optimal conditions, the proposed method had good linearity over the concentration ranges of 1.0-100 microg/L for 2, 4-dimethylaniline, 2-chloroanline, and N,N-dimethylaniline, and 1.5-150 microg/L for N,N-dimethylaniline and alpha-naphthylamine, with excellent correlation coefficients (R2 > or = 0.999), excellent detection sensitivity with LODs (S/N = 3) in the range of 0.39-0.63 microg/L, and precision in the range of 3.2-5.4% RSD (n = 6). Real water samples were analyzed with the established method, and good spike recoveries in the range of 86.3 to 98.9% were obtained. These results indicated that this method would be useful in the routine analysis of such pollutants.