Determination of fluoroquinolones in the environmental samples using vortex assisted dispersive liquid-liquid microextraction coupled with high performance liquid chromatography

A vortex assisted-dispersive liquid-liquid microextraction coupled with high performance liquid chromatograph equipped with a diode array detector technique for separation, preconcentration and determination of three fluoroquinolone antibiotics from wastewater was developed. Optimum conditions for the extraction, separation and preconcentration of the antibiotics were obtained using surface response methodology (RSM) based on the central composite design (CCD). Under optimum conditions, the limits of detection (LOD) and limit of quantification (LOQ) ranged from 0.63–1.2 ng L⁻¹ and 2.1–4 ng L⁻¹, respectively with the enhancement factors ranging from 48–83. The linear dynamic ranges were 2–800 for ciprofloxacin (CIPRO), and, 3–900 ng L⁻¹ for danofloxacin (DANO) and 4–1000 ng L⁻¹ for enrofloxacin (ENRO). Correlation coefficients were ranging from 0.9978 to 0.9989. The intraday (n = 15) and inter-day (n = 5) precisions (expressed in terms of % relative standard deviation (RSD) for 50 µg L⁻¹ of CIPRO, DANO and ENRO were in the range of 3.3–6% respectively. The developed method was used for the extraction, preconcentration and quantification of CIPRO, DANO and ENRO antibiotics in influent and effluent wastewater samples. In overall, vortex assisted-dispersive liquid-liquid microextraction coupled with liquid chromatograph equipped with a diode array detector (VA-DLLME/HPLC-DAD) demonstrated great potential for extraction, preconcentration and quantification of antibiotics in environmental water.