A selective and ultra-sensitive analytical method was developed for simultaneous determination of 11 fluoroquinolone (FQ) antibiotics in environmental and wastewater samples.  The method employs offline solid-phase extraction (SPE) and reversed-phase high performance liquid chromatography with fluorescence detection (HPLC-FLD).  A weak cation exchange SPE protocol was developed with a novel loading volume optimization algorithm and a cleanup step to remove background organic matter.  Various parameters were optimized to recover FQs from water/wastewater and analyte recovery was generally greater than 80%.  Chromatographic separation of the 11 FQs was achieved on a 150 mm pentafluorophenyl column using a gradient elution scheme with methanol, acetonitrile, and 20 mM phosphate buffer (pH = 2.4).  Excitation and emission wavelengths were individually optimized for each FQ using fluorescence spectrophotometry; the excitation and emission wavelengths were 276-296 nm and 444-506 nm, respectively.  Instrumental quantification limits were 20-100 pg of mass injected.  Of the 11 FQs investigated, seven FQs (i.e. ciprofloxacin, difloxacin, enrofloxacin, fleroxacin, norfloxacin, moxifloxacin, and ofloxacin) were detected during a four-month sampling campaign of wastewater and wastewater-impacted surface water.  Concentrations of FQs in raw wastewater, wastewater effluent, and wastewater-impacted surface water were 5-1292, 2-504, and 4-187 ng/L, respectively.

Determination of fluoroquinolone antibiotics in wastewater by solid-phase extraction high performance liquid chromatography with fluorescence detection

248th National Meeting (2014)

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