CoFe2O4 nanoparticles grafted multi-walled carbon nanotubes coupled with surfactant-enhanced spectrofluorimetry for determination of ofloxacin in human plasma

An efficient and simple magnetic solid phase extraction based on the use of CoFe3O4 nanoparticles grafted multiwalled carbon nanotubes (MWCNTs) as adsorbent coupled with surfactant enhanced spectrofluorimetric detection was developed for determination of ofloxacin from biological samples. The adsorbent uses the advantages of both magnetic nanoparticles (i.e., magnetic separation) and MWCNTs (i.e., high adsorption capacity). The main factors affecting the quantitative recovery including SDS concentration, pH, extraction and desorption times, adsorbent amount, and desorption conditions were investigated in detail. Under the optimized conditions, the calibration curves were linear over a wide concentration range of 100-750 ng mL^-1 with detection limit (LOD) of 23 ng mL^-1. The relative standard deviation (RSD %) of 3.3% for concentration of 250 ng mL^-1, n = 5 and the preconcentration factor of 93 were obtained. Finally, the proposed method was successfully applied to the extraction and preconcentration of ofloxacin in human plasma samples.