超高效液相色谱-串联质谱法测定水源水中6种β-内酰胺类抗生素的方法优化

Optimization of six β-lactam antibiotics determination in source water by UHPLC-MS/MS

[背景]目前对水体中β-内酰胺类抗生素的检测并未形成统一的标准方法,常用的检测方法污染重、危害大、耗时久。针对公共卫生突发事件,需要快速有效的检测方法。[目的 ]建立利用超高效液相色谱串联质谱法快速测定水源水中6种β-内酰胺类抗生素药物(阿莫西林、头孢他啶、头孢克洛、头孢拉定、青霉素V钾和氯唑西林)残留的检测方法。[方法 ]利用相对响应值评价基质效应。比较不同温度和保存时间水源水中β-内酰胺类药物的稳定性,确定最佳保存条件。水样经0.22μm微孔滤膜过滤,采用大体积进样方式,以0.1%甲酸水溶液和0.1%甲酸乙腈溶液作为流动相进行梯度洗脱,在Kinetex 2.6μm C18色谱柱上进行分离,采用电喷雾离子源正离子和多反应监测模式进行检测。[结果 ]通过基质曲线补偿基质效应的干扰。水样于采样瓶内4℃保存,24 h内进行分析可避免目标物降解。6种β-内酰胺类抗生素在线性范围内线性关系良好,检出限(信噪比S/N=3)为4~7 ng/L,定量限(S/N=10)为10~20 ng/L,加标回收率为84.8%~99.6%,相对标准偏差小于等于15.6%(n=6)。[结论 ]该方法简化了前处理过程,可以满足应急事件中同时检测水源水中6种β-内酰胺类抗生素残留的要求。

[Background] At present, no generally accepted standard methods are available for detection of β-lactam antibiotics in water, while conventional methods are polluting, harmful, and timeconsuming. Rapid and effective detection methods are therefore warranted in handling public health emergencies.[Objective] This study aims to establish a rapid method for detecting six β-lactam antibiotic residues in source water by ultra high performance liquid chromatography coupled with tandem mass spectrometry(UHPLC-MS/MS), including amoxicillin, ceftazidime, cefaclor, cephradine, phenoxymethylpenicillin potassium, and cloxacillin.[Methods] Matrix effects were evaluated with relative response value. The best storage conditions were determined by comparing the stability of β-lactam drugs in source water at different temperatures combined with different storage time. Water samples were filtered through a 0.22 μm rated microporous membrane using large volume injection, and then separated on Kinetex 2.6 μm C18 column with gradient elution using mobile phase of 0.1% formic acid and 0.1% acetonitrile. Electrospray ionization in positive mode and multiple reaction monitoring mode were used for detection.[Results] Matrix effect interference was compensated by matrix curve. The water samples were stored at 4℃ and analyzed within 24 h to avoid degradation of target chemicals. The six β-lactam antibiotics showed good linear relationships in designed ranges. The limits of detection(S/N=3) were 4-7 ng/L, the limits of quantification(S/N=10) were 10-20 ng/L, the adding standard recoveries were 84.8%-99.6%, and the relative standard deviations were all less than 15.6% or equal to(n=6).[Conclusion] The method is featured with simplified pre-treatment process and meets the requirement of simultaneously detecting six β-lactam antibiotic residues in source water in case of emergency events.