利用超声波辅助萃取(USE)技术,联合固相萃取(SPE)净化浓缩以及液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)技术,建立了城市污泥和河流底泥中微量-痕量大环内酯类、磺胺类抗生素、甲氧苄胺嘧啶和氯霉素的多目标定量分析方法。样品经USE提取,SPE净化后,用LC-ESI-MS/MS检测。选择C18为分析柱,甲醇、5mmol/L醋酸铵和0.1%甲酸混合溶液为流动相,选择在ESI正电离源下多反应监测(MRM)模式检测。对比了USE和加速溶剂萃取(ASE)对抗生素的萃取效率,优化了萃取条件。结果表明:USE和ASE对所选抗生素的萃取效率相当;而50%甲醇溶液在酸性条件下(pH2)萃取效率最好。抗生素的方法检出限为2.2~66.9ng/g(干重,下同);回收率介于74.7%~111.8%之间;相对标准偏差小于10.6%。应用此方法在广州某污水处理厂脱水污泥及某河涌底泥中检测到磺胺二甲基嘧啶、克拉霉素、脱水红霉素及罗红霉素等多种抗生素,含量为6.8~125.6ng/g。
A sensitive and feasible method was developed for the simultaneous determination of 10 trace antibiotic residues including sulfonamides, macrolides, trimethoprim and chloramphenicol in sewage sludge and sediment. The method involved ultrasonic extraction followed by solid phase extraction cleanup and liquid chromatography-tandem mass spectrometry coupled with electrospray ionization in positive mode (ESI + ). Liquid chromatography separations were carried out by C18 reversed phase column with the mobile phase of aqueous solution of 0.1% formic acid and 5 mmol/L ammonium acetate and methanol. The antibiotics were identified and determined by internal standard method in selected multiple reaction monitoring mode. The method detected limits were in the range from 2.2 ng/g to 66.9 ng/g dry weight for the investigated antibiotic compounds in sewage sludge. The recoveries ranged from 74.7% to 111.8% with the relative standard deviations of 1.2% - 10.6%. The method was successfully applied in a primary investigation of the occurrence of antibiotic residues in sewage sludge and a river sediment sample collected from Guangzhou. Sulfamethazine, trimethoprim, azithromycin, clarithromycin, dehydrated erythromyein and roxithromycin were detected in both the sewage sludge and the river sediment, ranging from 6.8 - 125.6 ng/g dry weight.