Sorption-fluorimetric determination of enrofloxacin with magnetite nanoparticles modified by mono and dicationic surfactants

Abstract

In the current study, superparamagnetic magnetite nanoparticles (MNP) were synthesized and surface-modified with two types of cationic surfactants: conventional monocationic cetyltrimethylammonium bromide (CTAB) and dicationic (gemini) surfactants of the 12-s-12 (s = 2, 4, 6) type to improve the stability of MNP and their adsorption properties with respect to enrofloxacin as a representative of fluoroquinolone antibiotics. The effect of various experimental factors: the pH of solution, the influence of concentration, the contact time and the quantity of the MNP sample were studied by using the batch technique. The characterization of the form, size of MNP, surface modification was performed with transmittance electron microscopy. It was established that the sizes of all MNP modified by cationic surfactants were varied between 8-9 nm and the thickness of organic shell was within 1.2-2.5 nm. It was found that the most high zeta-potential (+43 - +46) of modified MNP was at pH 3 and strongly decreased with increasing the pH value. The optimal sorption time of enrofloxacin was 15 min and in optimal conditions the extent of sorption is 80-90% as from pure water as buffer solution at pH 3 that was proved fluorimetrically by analyzing the enrofloxacin content in solution after MNP preconcentration.