Deep eutectic solvent-based extraction approach for separation of fluoroquinolones from soil and sediment followed by...

This study presents the first deep eutectic solvent-based extraction approach for separation of fluoroquinolones from soil and sediment. The developed extraction approach was coupled with high performance liquid chromatography with fluorometric detection. Various hydrophilic deep eutectic solvents were investigated for separation of fluoroquinolone antibiotics (ciprofloxacin, fleroxacin, gatifloxacin, lomefloxacin, and ofloxacin) from soil and sediment. It was established that deep eutectic solvent based on choline chloride, malonic acid and water demonstrated high extraction recovery (>90 %). The acidic media of deep eutectic solvent facilitated the protonation of the soil surface, leading to electrostatic repulsion between the soil matrix and the antibiotic molecules. This interaction enhanced the transfer of antibiotics into the extractant phase. To reduce limits of detection re-extraction of analytes into hexanoic acid was proposed. Validation parameters, including linearity, precision, accuracy, and robustness, were thoroughly evaluated. The developed procedure demonstrated limits of detection ranging from 2 to 3 μg kg^-1. The proposed approach eliminates the need for additional tedious and time-consuming purification by solid-phase extraction. It was successfully applied to real soil and sediment samples, showing no significant matrix interference.