Characterisation of the abiotic degradation pathways of oxytetracyclines in soil interstitial water using LC–MS–MS

摘要: The fate of oxytetracyclines (OTCs) in soil interstitial water was investigated and the structure a number degradation products elucidated time-related experiment. Apreviously developed separation method for LC–MS– MS able to base separate quantify OTC three its epimers applied. Compounds detected were 4-epi-oxytetracycline (EOTC) (tR ¼ 3:0 min), 4:4 a-apo-oxytetracycline (a-apo-OTC) 11:4 min) b-apo-oxytetracycline (b-apo-OTC) 18:4 min). Furthermore, we tentatively identified 4-epi-N -desmethyl-oxytetracycline (E-N-DM-OTC) N (N -DM-OTC) 3:5), -didesmethyl-oxytetracycline -DDM-OTC), (E-N-DDM-OTC) 3:7 4.7 2-acetyl-2-decarboxamido-oxytetracycline 8:7) all samples. Most compounds only present trace concentrations (less than 2%) relative parent OTC. EOTC on other hand formed up ratio 0.6 concentration. Only EOTC, E-N-DM-OTC, -DM-OTC, -DDM-OTC E-N during All probably as impurities spiked formulation they declined concentration from start Half-lives (T1=2, days) OTCs order 2 days 270 (b-apo-OTC). 2003 Elsevier Science Ltd. rights reserved.