Simultaneous High-Throughput Determination of 77 Antibiotics in Environmental Water Using Automated SPE-UPLC-MS/MS

Antibiotics, as a class of emerging contaminants, have been frequently detected in aquatic environments and have become a focus of concern for environmental protection agencies worldwide. To enable effective control of antibiotic residues in water bodies, there is an urgent need to establish accurate, sensitive, rapid, and high-throughput analytical methods. This study developed a simultaneous detection method for 77 antibiotics from three major classes in water environments based on solid-phase extraction coupled with ultra-performance liquid chromatography–tandem mass spectrometry. Water samples were filtered through a 0.45 μm membrane, disodium ethylenediaminetetraacetate was added, and the pH was adjusted to 2.5. The samples were purified using a PLS-3 solid-phase extraction column, concentrated under nitrogen blow-down, and reconstituted with a 10 % methanol–water solution, Separation was performed on a LUNA OMEGA C18 column, and detection was carried out in electrospray positive ion mode using scheduled multiple reaction monitoring, with quantification by the internal standard method. The results showed good linearity for the 77 antibiotics within their respective concentration ranges. The average recoveries at low, medium, and high spiked levels ranged from 63.2 % to 124.3 %, with relative standard deviations between 0.7 % and 14.5 %. The method quantification limits were 0.1 ng/L–0.6 ng/L. This method was applied to analyze 68 source water and secondary water supply samples, detecting 18 antibiotics, including azithromycin, clindamycin, sulfadiazine, and lomefloxacin, with an overall detection rate of 25.7 %. The method is simple, rapid, and suitable for high-throughput and accurate detection of multiple antibiotic residues in environmental water samples.