Improved methodology to survey veterinary antibiotics in environmental samples using µSPEed microextraction followed by ultraperformance liquid chromatography

A μSPEed microextraction combined with ultra-performance liquid chromatography (UHPLC) with UV detection was developed for analysing six veterinary antibiotics (tetracycline, chlortetracycline, oxytetracycline, doxycycline, sulfamethoxazole, and trimethoprim) in environmental samples. To optimise extraction, 12 sorbent cartridges, sample loading cycles, volumes, and pH were assayed. The PS/DVB-RP cartridge, three 250 μL sample loading cycles, and two 50-µL elutions with acidified methanol yielded maximum efficiency. The method was validated with optimised fast chromatographic separation, showing good linearity (R2 > 0.99), precision (RSD < 20%), and recoveries between 46-86%. Detection and quantification limits ranged from 0.30-1.23 μg L^-1 and 0.92-3.73 μg L^-1, respectively. The optimised μSPEed/UPLC-PDA efficiently analysed environmental water samples, requiring only 6 min extraction, 6 min analysis, and 500 μL sample, surpassing alternative methods in speed, workloads and reproducibility. The cost-effective, commercially available equipment facilitates accessibility for laboratories and adaptability for analysing selected antibiotics in diverse matrices, including food and environmental samples.