Dispersive liquid–liquid microextraction combined with ultra-high performance liquid chromatography for the simultaneous determination of 25 sulfonamide and quinolone antibiotics in water samples

In this work, a dispersive liquid–liquid microextraction (DLLME) procedure combined with ultra-high performance liquid chromatography with diode-array detection was developed to determine 25 antibiotics in mineral and run-off waters. Optimum DLLME conditions (5 mL of water at pH = 7.6, 20% (w/v) NaCl, 685 μL of CHCl3 as extractant solvent, and 1250 μL of ACN as disperser solvent) allowed the repeatable, accurate and selective determination of 11 sulfonamides (sulfanilamide, sulfacetamide, sulfadiazine, sulfathiazole, sulfadimidin, sulfamethoxypyridazine, sulfadoxine, sulfamethoxazole, sulfisoxazole, sulfadimethoxine and sulfaquinoxaline) and 14 quinolones (pipemidic acid, marbofloxacin, fleroxacin, levofloxacin, pefloxacin, ciprofloxacin, lomefloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, moxifloxacin, oxolinic acid and flumequine). The method was validated by means of the obtention of calibration curves of the whole method as well as a recovery study at two levels of concentration. The LODs of the method were in the range 0.35–10.5 μg/L with recoveries between 78% and 117%.

Figure optionsDownload as PowerPoint slideHighlights
► A DLLME–UHPLC-DAD method was developed to determine antibiotics in water.
► A total of 25 compounds (11 sulfonamides and 14 quinolones) was analyzed.
► Relative recoveries values of the method were between 74% and 117%.
► The procedure is simple, fast and reliable to determine the selected antibiotics.