Comparison of solid phase extraction using micellar desorption combined with LC-FD and LC-MS/MS in the determination of antibiotics fluoroquinolone residues in sewage samples

Abstract

A new “green” methodology, free of hazardous solvents, was developed for the extraction and determination of five fluoroquinolones (levofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, and sarafloxacin) in environmental water matrices. The method is based on solid-phase extraction (SPE) coupled to liquid chromatography (LC) with fluorescence and mass spectrometry detection. In this work, we replaced an organic solvent by a micellar media in the desorption step of the SPE process. This combination has never before been optimized and applied to environmental samples analysis. After SPE extraction optimization, a detailed study on the optimum conditions for micellar desorption (i.e., surfactant type, concentration, and volume) was performed. The proposed method was compared to the conventional SPE procedure using methanol as the desorbing agent and tested on several aqueous environmental samples, including seawater, groundwater, and wastewater. Extraction efficiencies of 73%–97% were obtained for all five compounds with relative standard deviations below 11% in all matrices. Finally, real sewage samples from a hospital and wastewater treatment plant were analyzed with both conventional and micellar desorption using fluorescence and mass spectrometry detection.