Abstract: We have developed an analytical method for simultaneous determination of seven fluoroquinolones(FQs)in sewage sludge based on solid-phase extraction and high performance liquid chromatography with fluorescence detection (HPLC/FLD) in this study to monitor the FQ contents and levels in sewage sludge. The homogenized sludge sample was subjected to pH 3 phosphate buffer/acetonitrile (1∶1, V∶V) solution treatment, then loaded onto an Oasis HLB solid phase column after vortexing and eluted with methanol solvent. The FQs in the extract were detected by HPLC/FLD with acetonitrile and 0.1% formic acid as the mobile phase, and quantified using external standards. The standard curves for all the compounds were linear over the concentration ranges of 0.005 to 1.0 mg/L with R2 equaling 0.99270.9998. The spiked recoveries at 0.05, 0.5 and 1.0 mg/L levels ranged between 78.3%106.4%, with relatives standard deviations (RSD) ranging between 3.68%12.06%(N=5). The limit of detection (LOD) was between 0.0010.01 mg/kg, and the limit of quantification (LOQ) ranged between 0.00460.0384 mg/kg. We used this method to analyze seven FQs in sewage sludge collected from three sewage treatment plants in Beijing. and found the FQ concentrations to be from ND to 1.09 mg/kg in tested samples.

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