The Analytical Method Research On Chiral Ofloxacin In Sewage

In this paper, a robust analytical method has been developed and validated for the trace analysis of ofloxacin enantiomers in sewage using two-step solid phase extraction purification and liquid chromatography with fluorescence detection (LC-FL). Ofloxacin enantiomers were separated on an Aglient TC-C-18 column using MeOH-water containing 4 mmol/L CuSO₄ and 5 mmol/L 1-isoleucine as mobile phase. The ofloxacin enantiomers were first extracted by a weak cation-exchange resin (WCX), then further purified by mixed mode of anion-exchange resin (MAX), resulting in ofloxacin recoveries generally above 95%. The limit of quantification was 0.08μg/L for each enantiomer.In order to confirm the utility of the LC-FL methodology for analysis of environmental samples, sewage samples taken from two STPs (Sewage Treatment Plants) of Beijing were determined. Total concentrations of both enantiomers, with a range of 488～1067 ng/L. Much higher concentrations of (S)-ofloxacin (393～910 ng/L) than (R)-ofloxacin (83～175ng/L) occurred in all of the samples, which is accordance with their usage in medical treatment.