中科院西北特色植物资源化学重点实验室/甘肃省天然药物重点实验室知识库

A new mode of ionic liquid based dispersive liquid–liquid microextraction (IL-DLLME) is developed. In this work, [C₆MIm][PF₆] was chosen as the extraction solvent, and two kinds of hydrophilic ionic liquids, [EMIm][BF₄] and [BSO₃HMIm][OTf], functioned as the dispersive solvent. So in the whole extraction procedure, no organic solvent was used. With the aid of SO₃H group, the acidic compound was extracted from the sample solution without pH adjustment. Two phenolic compounds, namely, 2-naphthol and 4-nitrophenol were chosen as the target analytes. Important parameters affecting the extraction efficiency, such as the type of hydrophilic ionic liquids, the volume ratio of [EMIm][BF₄] to [BSO₃HMIm][OTf], type and volume of extraction solvent, pH value of sample solution, sonication time, extraction time and centrifugation time were investigated and optimized. Under the optimized extraction conditions, the method exhibited good sensitivity with the limits of detection (LODs) at 5.5 μg L^_1and 10.0 μg L^_1 for 4-nitrophenol and 2-naphthol, respectively. Good linearity over the concentration ranges of 24–384 μg L^_1 for 4-nitrophenol and 28–336 μg L^_1 for 2-naphthol was obtained with correlation coefficients of 0.9998 and 0.9961, respectively. The proposed method can directly extract acidic compound from environmental sample or even more complex sample matrix without any pH adjustment procedure.