Determination of fluoroquinolone antibiotics in industrial wastewater by high-pressure liquid chromatography and thin-layer chromatography-densitometric methods

Two methods were described for the simultaneous determination of ciprofloxacin HCl (CIP) and moxifloxacin HCl (MOX) in their binary mixture present in industrial wastewater. A solid-phase extraction procedure (SPE) based on retention on HLB OASIS cartridges and elution with a mixture of methanol-water in acidic medium was preformed, and then both fluoroquinolones were separated using two chromatographic methods. The first method was based on high-performance liquid chromatographic separation of the two drugs on reversed-phase Zorbax C18 column. The mobile phase consisted of monobasic potassium phosphate (50 mM, pH 2.5, adjusted with phosphoric acid) and acetonitrile (80:20, v/v). Flow rate was 1 mL min−1. Quantitation was achieved with ultraviolet (UV) detection at 278 nm. Linearity was found to be over the concentration range of 1–50 μg mL−1 for both CIP and MOX. The second method was based on the thin-layer chromatographic (TLC) separation of the two drugs followed by densitometric measurements of their...