Temperature-controlled ionic liquid dispersive liquid phase microextraction combined with ultra-high-pressure liquid chromatography for the rapid determination of triclosan, triclocarban and methyl-triclosan in aqueous samples

As extraction solvents, ionic liquids have green characteristics. In this study, an environmentally benign analytical method termed temperature-controlled ionic liquid dispersive liquid phase microextraction (TIL-DLME) combined with ultra-highpressure liquid chromatography (UHPLC)-tunable ultraviolet detection (TUV) was developed for the pre-concentration and determination of triclosan (TCS), triclocarban (TCC) and methyl-triclosan (M-TCS) in water samples. Significant parameters that may affect extraction efficiencies were examined and optimized, including the types and amount of ionic liquids, volume of the diluent, heating temperature, cooling time, salt effect and pH value. Under the optimum conditions, linearity of the method was observed in the ranges of 0.0100-100 μg L^-1 for TCS and M-TCS, and 0.00500-50.0 μg L ^-1 for TCC with correlation coefficients (r ²) > 0.9903. The limits of detection (LODs) ranged from 1.15 to 5.33 ng L ^-1. TCS in domestic water and TCC in reclaimed water were detected at the concentrations of 1.01 and 0.126 μg L^-1, respectively. The spiked recoveries of the three target compounds in reclaimed water, irrigating water, waste water and domestic water samples were obtained in the ranges of 68.4%-71.9%, 61.6%-87.8%, 58.9%-74.9% and 64.9%-92.4%, respectively. Compared with the previous dispersive liquid-liquid microextraction method (DLLME) about the determination of TCS, TCC and M-TCS, this method is not only more environmentally friendly but also more sensitive.