Cefquinome (CEQ), the fourth generation of cephalosporins, has been widely used in practice for the treatment of bacterial infections due to its broad antimicrobial spectrum, stability, and stronger antibacterial activity. However, the wide use of CEQ can cause an environmental risk via animal excretion. In the current study, the environmental fate of CEQ was investigated. The migration rate of CEQ from soil to the aquatic environment was approximately 60%. The half-life (T_1/2) of CEQ degradation in the water ranged from 0.96 to 13.75 d. Our results showed that the temperature, illumination, and pH had an effect on the degradation rate, and the rate of CEQ degradation was significantly accelerated under high temperatures. CEQ was more stable in acidic environments than in alkaline. E-isomer of CEQ and △³-isomer of CEQ were the major degradation metabolites identified by UPLC-Q-Orbitrap MS. The product ion m/z 293.041 was the typical fragment ion for E-isomer of CEQ, and m/z 201.044 and m/z 152.016 were the typical fragment ion for △³-isomer of CEQ. The degradation metabolites exhibited lower antibacterial activity, simultaneously, the toxicity of the E-isomer of CEQ should pay more attention to.

头孢喹诺（CEQ）是第四代头孢菌素类药物，由于其抗菌谱广、稳定性好、抗菌活性强等优点，在临床上被广泛用于治疗细菌感染。然而，CEQ 的广泛使用可能会带来环境风险通过动物排泄物。在目前的研究中，研究了 CEQ 的环境归宿。CEQ 从土壤到水环境的迁移率约为 60%。CEQ在水中降解的半衰期(T _{1/2 )为0.96～13.75 d。}结果表明，温度、光照和pH对降解速率有影响，高温下CEQ降解速率明显加快。CEQ 在酸性环境中比在碱性环境中更稳定。CEQ的E-异构体和CEQ的△ ^3-异构体是UPLC-Q-Orbitrap MS鉴定的主要降解代谢物。产物离子 m/z 293.041 是 CEQ E 异构体的典型碎片离子， m/z 201.044 和 m/z 152.016 是△ ^{3的典型碎片离子}-CEQ 的异构体。降解代谢物表现出较低的抗菌活性，同时CEQ的E-异构体的毒性应引起重视。