Ionic Liquid-based Ultrasound-assisted In-situ Solvent Formation Microextraction and High-performance Liquid Chromatography for the Trace Determination of Polycyclic Aromatic Hydrocarbons in Environmental Water Samples

A green and efficient ionic liquid-based ultrasound-assisted in-situ solvent formation microextraction (IL-UA-ISFME) in combination with high-performance liquid chromatographyultraviolet detection (HPLC-UV) has been successfully developed for the trace determination of five selected polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. In this method, a hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to sample solution containing an ion-pairing agent (NaPF6). The analytes were extracted into the ionic liquid phase while the microextraction solvent was dispersed through the sample by utilizing ultrasonic radiation. The sample was then centrifuged and extracting phase retracted into the microsyringe, diluted with acetonitrile, and injected to HPLC. In the beginning, effective parameters controlling the performance of the microextraction process were studied in detail and optimized. The limit of detections (LOD, S/N = 3) were in the range of 0.32-0.79 μg L-1 while the RSD% values were below than 5.2% (n = 6). A good linearity (0.997 ≥ r2 ≥ 0.992) and a broad linear over the concentration ranges from 1 to 500 μg L-1 were achieved. The method was ultimately applied for the preconcentration and sensitive determination of the PAHs in several environmental water samples. The accuracy of the method in the real samples was tested by the relative recovery experiments with results ranging from 90-106%, which confirmed that complicated matrixes had almost little effect on the developed analytical procedure.