Application of a supramolecular solvent as the carrier for ferrofluid based liquid-phase microextraction for spectrofluorimetric determination of levofloxacin in biological samples

In the present study, a novel and environmentally friendly liquid-phase microextraction method based on the application of a supramolecular solvent as a carrier for ferrofluid was proposed for spectrofluorimetric determination of levofloxacin (LEVO). The ferrofluid was composed of oleic acid-coated magnetic particles and the supramolecular solvent as the extraction solvent. The supramolecular solvent is water-immiscible nanostructured liquid that was produced from coacervation of decanoic acid aqueous vesicles in the presence of tetrabutyl ammonium (Bu4N+). As the ferrofluid can be attracted by using a magnet, no special devices and complicated operations were needed for phase separation. The important parameters affecting the microextraction efficiency including pH, volume of the extraction solvent, salt effect and extraction time were investigated and optimized. Under optimum conditions, the calibration curve for LEVO determination showed good linearity in the range of 1-200.0 ng mL(-1) (R-2 = 0.9987). The repeatability and reproducibility (RSD%) of 20 ng mL(-1) LEVO were 2.9% and 4.4%, respectively and the limit of detection (S/N = 3) was estimated to be 0.2 ng mL(-1). The proposed method was successfully applied to the extraction and determination of levofloxacin in biological samples.