Development of deep eutectic solvents based ferrofluid for liquid phase microextraction of ofloxacin and sparfloxacin in water samples

A smart material based on ferrofluid deep eutectic solvents graphene oxide magnetite (GO@Fe3O4-DES FF) was successfully synthesised by adding choline chloride-ethylene glycol DES as carrier solvent onto GO@Fe3O4 composite. The morphological, functional group, and magnetic characteristics of the synthesised materials were characterised by elemental analysis, Fourier Transform-infrared spectroscopy, scanning electron microscopy, transmission electron microscopes and, vibrating sample magnetometer. The adsorption performances of ofloxacin (OFL) and sparfloxacin (SPR) were evaluated based on kinetic, isotherm, and thermodynamic models. The GO@Fe3O4-DES FF material was used as ferrofluid sorbent for liquid phase microextraction (LPME) of OFL and SPR prior to HPLC-UV analysis. The effect of several parameters on the peak areas of OFL and SPR including type of desorption solvent, ferrofluid volume, extraction time, desorption solvent volume, desorption time, solution pH, and sample volume were optimized. Under the optimum conditions, good linearity was achieved (1-1500 mu g/L) with a coefficient of determination (R2) of 0.9921 and 0.9956 for OFL and SPR, respectively. The LOD values were recorded in the range of 0.0063-0.0058 mu g/L. The developed GO@Fe3O4-DES FF LPME method was applied for the determination of OFL and SPR in water samples collected from Langat River Basin, Selangor, with recovery values ranging from 70.3 to 121.5 %. Based on the results obtained, the developed GO@Fe3O4-DES FF LPME method demonstrated excellent sensitivity and efficiency for the extraction of OFL and SPR in water samples. It showed great potential as an alternative method for the extraction of pharmaceutically active contaminants in the aquatic system.