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


1 Department of Applied Chemistry, Faculty of Science, Islamic Azad University, South Tehran branch, Tehran, Iran

2 Research Institute of Petroleum Industry (RIPI), Tehran, Iran


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.