Up-and-down shaker-assisted ionic liquid-based dispersive liquid-liquid microextraction of benzophenone-type...

Sun protection is an important part of our lives. UV filters are widely used to absorb solar radiation in sunscreens. However, excess UV filters constitute persistent groups of organic micropollutants present in the environment. An environmentally friendly ionic-liquid-based up-and-down shaker-assisted dispersive liquid-liquid microextraction device combined with ultra-performance liquid chromatography coupled with photodiode-array detection has been developed to preconcentrate three UV filters (benzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone) from field water samples. In this method, the optimal conditions for the proposed extraction method were: 40 μL [C8MIM][PF6 ] as extraction solvent and 200 μL methanol as disperser solvent were used to extract the UV filters. After up-and-down shaking for 3 min, the aqueous solution was centrifuged at 5000 rpm speed, then using microtube to collect the settled extraction solvent and using ultra-performance liquid chromatography for further analysis. Quantification results indicated that the linear range was 2-1000 ng/mL. The LOD of this method was in the range 0.2-1.3 ng/mL with r(2) ≥ 0.9993. The relative recovery in studies of different types of field water samples was in the range 92-120%, and the RSD was 2.3-7.1%. The proposed method was also applied to the analysis of field samples.