Magnetic Solid-Phase Extraction and Fluorimetric Determination of Some Fluoroquinolones

An approach to estimating the concentration of fluoroquinolones based on their sorption and preconcentration by magnetic solid-phase extraction on magnetite nanoparticles modified with cetyltrime-thylammonium bromide cations (CTAB) or polyethyleneimine cationic polyelectrolyte (PEI), and the fluorimetric determination of these preparations is proposed. The optimal conditions for the modification of magnetite nanoparticles by PEI and CTAB cations are found. Using examples of enrofloxacin, levofloxacin, and pefloxacin, patterns of their sorption and preconcentration on modified magnetite nanoparticles are found. Fluorimetric procedures for the determination of enrofloxacin and levofloxacin in river water, a plasma substitute, and veterinary preparations are tested.