Determination of quinolone antibiotics in environmental water using automatic solid-phase extraction and isotope dilution ultra-performance liquid chromatography tandem mass spectrometry

The widespread use of quinolones in humans and animals has become a major threat to public health. In this study, a simple, rapid, sensitive, and high throughput method based on automatic solid-phase extraction and isotope dilution ultra-performance liquid chromatography tandem mass spectrometry was described for the determination of trace quinolones in environmental water. The proposed automated solid-phase extraction method was initially optimized, and the optimum experimental conditions found were 1 L water sample with 0.5 g/L Na2EDTA (pH 3) extracted and enriched by CNW Poly-Sery HLB cartridge at a flow rate of 50 mL/min and eluted by 8 mL of methanol. The linearity of the method ranged from 0.05 to 100 μg/L for 15 quinolones, with correlation coefficients ranging from 0.9993 to 0.9999. The limits of detection were in the low ng/L level, ranging from 0.005 to 0.051 ng/L. Finally, the optimized method was applied for determining trace levels of 15 quinolones in Wahaha pure water, tap water, river water, and seawater samples with good recoveries of 93 %-119 % and satisfactory relative standard deviations of 0.1 %-13.9 %. Fourteen quinolones were detected, and ofloxacin was the predominant congener in river water and seawater.