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

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 (R-2) 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 similar to 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.

Automated summary

A dispersive liquid-liquid microextraction technique using a low-density hydrophobic deep eutectic solvent was developed for the determination of chlorophenols in water samples. The method showed good linearity, low detection limits, and high precision. The developed technique has advantages such as selectivity, use of less harmful solvent, avoidance of toxic organic solvents, and short extraction time.