Simultaneous determination of selected antimicrobial agents in sewage sludge by pressurized liquid extraction and LC -MS/MS
In the present study, an efficient analytical method for the simultaneous determination of an amphenicol, sulfonamides (SAs) and fluoroquinolones (FQs) in a sewage sludge matrix was developed by high performance liquid chromatography in tandem with mass spectrometry (LCMS). The selected antibiotics were extracted from the sewage sludge sample by pressurized liquid extraction (PLE) followed by solid phase extraction (SPE) as a clean-up step. Compounds separation was achieved using a mobile phase gradient composition of hexafluoro-isopropanol buffer and methanol. Recoveries of all eight compounds were in the range from 69% to 166%. Limit of quantification ranged from 0.6 ng/g for FQs to 9.3 ng/g for SAs. As most of the compounds showed significant matrix effects, the method was validated using the standard addition method which reduced this effect very significantly.
antibiotic residue analysis, LC-MS, method development, pressurized liquid extraction