Analysis of veterinary antibiotic residues in swine wastewater and environmental water samples using optimized SPE-LC/MS/MS

Strategies for sample preparation, solid-phase extraction (SPE), clean-up, and detection conditions of an optimized solid-phase extraction-liquid chromatography/mass/mass spectrometry (SPE-LC/MS/MS) method for determining multi-residues of four classes of widely used antibiotics in pig farms, sulfonamides (SAs), fluoroquinolone (FQs), tetracycline (TCs) and chloramphenicol (CAP) were presented. The multi-residue analysis was used in MS analysis, selecting two precursor ions to produce ion transitions for each target compound. Samples of swine wastewater, lake water and groundwater collected from two pig farms in central China were used to test the applicability of the multi-residue analysis method. The average antibiotics concentrations in groundwater, lake water, final effluent and influent swine wastewater were, respectively, 1.6–8.6, 5.7–11.6, 7.9–1172.3 and 8.5–21692.7 ng L−1 in summer; respectively, 2.0–7.3, 6.7–11.7, 5.8–409.5 and 32.8–11276.6 ng L−1 in winter. The limits of quantification were 0.8–4.1, 1.4–5.5, 1.8–11.5 and 6.4–104.4 ng L−1, respectively, in groundwater, lake water, final effluent and influent swine wastewater. Results of multi-residue analysis of antibiotics in the samples indicate that SAs, FQs and TCs were widely used veterinary medicines in the pig farms. As compared with previous studies, higher elimination rates (more than 80%) of the antibiotics (except DC) were observed in effluent in this study. More detailed work is indispensable to investigate the fate and transport of antibiotics in the environment and to find out cost-effective approaches of removing antibiotics from swine wastewater and contaminated sites.