Extraction and detection of chlorophenols in water samples using deep eutectic solvent-based dispersive liquid–liquid microextraction coupled with HPLC-UV

Abstract

A dispersive liquid–liquid microextraction (DLLME) technique utilizing a low-density hydrophobic deep eutectic solvent (LD-HDES) based on the combination of DL-Menthol and L-lactic acid was developed. The developed sample preparation technique (LD-HDES-DLLME) coupled with liquid chromatography equipped with an ultraviolet detector (HPLC-UV) method was applied to determine the chlorophenols (CPs) in waters (drinking water, river water, and wastewaters). The DL-Menthol as a hydrogen bond acceptor (HBA) and L-lactic acid used as a hydrogen bond donor (HBD) for the deep eutectic solvent synthesis. The formed deep eutectic solvent was confirmed by FTIR, and the factors affecting the LD-HDES-DLLME process were carefully optimized. The developed LD-HDES-DLLME-HPLC-UV method exhibited good linearities for all studied CPs, correlation coefficient (R2) values ≥0.9993, LODs were in between 0.02 and 0.05 ng mL−1 for all the CPs, LOQs obtained were in between 0.06 and 0.15 ng mL−1, the method precision (RSDs) values are ≤8.8 %. The relative recoveries of the developed technique were studied at three levels; the obtained recoveries are between 90 ∼ 119 %, with RSDs ≤ 9.5 % for studied water samples. The proposed LD-HDES-DLLME-HPLC-UV method possesses substantial merits such as selectivity, use of less harmful solvent for the extraction, avoiding the use of toxic organic solvents, and short extraction time.