大体积进样液相色谱-串联质谱法测定海水中22种抗生素

Determination of 22 antibiotics in seawater by liquid chromatography-tandem mass spectrometry with large-volume injection

本研究针对海水环境中抗生素浓度较低的情况,基于固相萃取(SPE)结合大体积进样液相色谱-串联质谱联用技术(LVI-LC-MS/MS),建立适用于海水中痕量抗生素检测的新方法,并用于近海海湾常见抗生素的分析。对离线SPE及液相色谱在线SPE大体积进样条件优化后,检测仅需80 mL海水样品。海水样品经离线HLB固相萃取柱富集后,采用LVI-LC-MS/MS检测(进样量50μL),海水中22种抗生素在0.07~12.50 ng/L范围内均具有良好的线性关系(R^(2)>0.990),方法检出限范围为0.003~0.63 ng/L,定量限范围为0.01~1.25 ng/L,各种抗生素的加标回收率为55.87%~113.49%,精密度(相对标准偏差,RSD)为1.13%~12.60%,表明该方法灵敏度高、准确性好。与常规小体积进样方法相比,该方法能有效提升样品利用率,显著降低海水样品用量和前处理时间,可满足海水环境中痕量抗生素的检测要求。最后,采用该方法对山东近海两个典型养殖海湾——四十里湾和桑沟湾海水中的抗生素进行了检测,在36个表、底层海水样品中共检出9种常见抗生素,主要为氟苯尼考(florfenicol,FF)、磺胺甲基异恶唑(sulfamethoxazole,SMX)、甲氧苄啶(trimethoprim,TMP)、克拉霉素(clarithromycin,CTM)、脱水红霉素(dehydrated erythromycin,ERY-H2O)、罗红霉素(roxithromycin,ROX)等,总平均浓度范围为0.05~8.19 ng/L。

A new method was developed for the simultaneous determination of various trace antibiotics in seawater using solid-phase extraction(SPE)combined with large-volume injection liquid chromatographytandem mass spectrometry(LVI-LC-MS/MS)and applied to the analysis of common antibiotics in nearshore bays.The optimization of offline SPE and online SPE(large volume injection)conditions was investigated.Under the optimal conditions,only 80 mL of seawater samples need to be enriched via an offline HLB SPE column,followed by detection through LVI-LC-MS/MS(injection volume of 50μL).Remarkably,the 22 antibiotics found in seawater exhibited a high level of linearity(R^(2)>0.990)within the concentration range of 0.07 to 12.50 ng/L.The lowest limit of detection(LOD)for these antibiotics is between 0.003 and 0.63 ng/L,while the limits of quantification(LOQ)range from 0.01 to 1.25 ng/L.Satisfactory recoveries(55.87%-113.49%),precision(relative standard deviations,RSD=1.13%-12.60%)were also achieved,demonstrating the high sensitivity and precision of the proposed method.Moreover,compared to the conventional small-volume injection method,this method effectively improved sample utilization rate and significantly reduced both the required seawater sample volume and pretreatment time.Therefore,the method meets the requirements for the detection of trace antibiotics in the seawater environment.To test the effectiveness of the method,antibiotics were detected in seawater samples collected from two mariculture bays in Shandong,namely Sishili bay and Sanggou bay.A total of 9 common antibiotics were detected in 36 samples of surface and bottom seawater,mainly florfenicol,sulfamethoxazole,trimethoprim,clarithromycin,dehydrated erythromycin,and roxithromycin,with total average concentrations ranging from 0.05 to 8.19 ng/L.