Screening fluorescent method for the fluoroquinolone family in groundwater samples from intensive livestock production systems

A fast and simple screening fluorescent method was developed and applied for detection of quinolones in groundwater samples. The experimental conditions for quinolone family detection in 96-well plates were acid media (pH = 4.85) from acetate buffer solution (0.1 mol L−1) and 5.8 × 10−3 mol L−1 of anionic surfactant sodium dodecyl sulfate (SDS) as micellar media at excitation and emission wavelengths of 280 and 450 nm, respectively. The developed method was validated to guarantee the quality of the results reported. Thus, the decision limit (CCα) of ciprofloxacin of 6.8 μg L−1, the most prescript quinolone in our country, was selected as the cut-off level to classify the water samples as ‘suspect’ or ‘negative’ referred to quinolone content. The method showed good recoveries ranging between 80 and 114% for 6.8 μg L−1 ciprofloxacin with relative standard deviation values lower than 13%. Moreover, other families of antibiotics such as aminoglycoside, penicillin, macrolide, sulfonamide and tetracycline did not present interference in the quinolone detection. Groundwater samples from Argentine regions with intensive livestock activities were analysed by this method, and the results had a good correlation with a reference method based on ultraperformance liquid chromatography coupled to mass spectrometry.