Simultaneous synthesis of a deep eutectic solvent and its application in liquid–liquid microextraction of polycyclic aromatic hydrocarbons from aqueous samples

Abstract

In the present study, a new generation of solvents, named deep eutectic solvents, were simultaneously synthesized and used as an extraction solvent in a liquid–liquid microextraction method for the extraction and preconcentration of some polycyclic aromatic hydrocarbons from aqueous samples prior to their determination by high performance liquid chromatography-diode array detection. In this method, choline chloride and p-chlorophenol (at a 1 : 2 molar ratio) are added to an aqueous phase containing the target analytes and the mixture is shaken manually to obtain a homogeneous solution. After heating, choline chloride and p-chlorophenol form a deep eutectic solvent in whole parts of the solution and a cloudy state is obtained. The solution is centrifuged and the sedimented phase is injected into the separation system. Some important parameters such as deep eutectic solvent composition, ionic strength, pH and temperature of aqueous phase, and centrifuge rate and time were studied. Under the optimum conditions, enrichment factors and extraction recoveries were obtained in the 586–632 and 88–95% ranges, respectively. The linear ranges of calibration curves were wide and the limits of detection and quantification were between 0.19 and 0.92 and 0.61–3.0 ng mL⁻¹, respectively. This method is very simple, rapid and efficient.