固相萃取-气相色谱-串联质谱法同时测定武汉市普通人群血清中35种有机氯农药与多氯联苯

Simultaneous determination of 35 organochlorine pesticides and polychlorinated biphenyls in the serum of the general population in Wuhan by solid phase extraction-gas chromatography-tandem mass spectrometry

有机氯农药(OCPs)和多氯联苯(PCBs)是两类重要的持久性有机污染物,可在环境介质中长期存在,并通过多种途径进入人体,导致人体的高暴露风险。OCPs和PCBs对人体存在诸多健康危害,精准定量人体内OCPs和PCBs的暴露水平是健康效应评价的关键。该研究基于固相萃取-气相色谱-串联质谱联用技术(SPE-GC-MS/MS)建立了同时检测100μL血清中35种OCPs和PCBs的分析方法。血清样品经尿素沉淀蛋白后,采用Oasis■HLB小柱净化,正己烷-二氯甲烷混合溶液(1∶1,v/v)洗脱,氮吹近干,正己烷定容,多反应监测(MRM)模式检测,内标法定量分析。结果表明,OCPs和PCBs在0.05~50.0 ng/mL范围内线性关系良好,检出限在1.2~71.4 ng/L之间。35种目标分析物的加标回收率在72.6%~142%之间,相对标准偏差小于25%。利用所建立的方法检测了武汉市普通人群血清样本中OCPs和PCBs的浓度水平,结果表明武汉市普通人群广泛暴露于OCPs和PCBs,且以OCPs为主。有8种OCPs和7种PCBs检出率高于50%,其中p,p′-滴滴伊、p,p′-滴滴滴和甲氧滴滴涕检出率达100%,非类二噁英PCBs是PCBs的主要成分。血清中OCPs浓度随年龄增长呈升高趋势,在60岁以上存在性别差异;不同性别、年龄人群血清中PCBs浓度无统计学差异。该方法样本用量少,操作简便,具有较高的准确度和精密度,适用于环境健康研究中大量人群血清样本中痕量OCPs和PCBs的生物监测。

Owing to their persistence,ease of accumulation in organisms,and high toxicity,the use of persistent organic pollutants(POPs)has been limited ever since the Stockholm Convention on Persistent Organic Pollutants was signed in 2001 by the United Nations Environment Programme(UNEP).As typical POPs,organochlorine pesticides(OCPs)and polychlorinated biphenyls(PCBs)can persist in the environment for long periods.They can enter human bodies through many pathways and pose a high exposure risk to humans.OCPs and PCBs can lead to endocrine disruption,neurotoxicity,immunotoxicity,reproductive toxicity,and cancer in human beings.Accurate quantification of pollutant load levels in vivo is crucial for the evaluation of health effects.In this study,a rapid and sensitive method based on solid phase extraction-gas chromatography-tandem mass spectrometry(SPE-GC-MS/MS)was developed for the simultaneous determination of 35 OCPs and PCBs in serum.Accordingly,100μL of the serum sample was gently mixed with the isotope-labeled internal standard solution(10μL)to obtain a final mass concentration of 10 ng/mL for each internal standard.After incubation overnight,the samples were mixed with 100μL purified water for dilution.After protein precipitation with 100 mg urea,the serum samples were passed through preconditioned Oasis■ HLB cartridges,washed with 6 mL purified water,and eluted with 5 mL hexane-dichloromethane(1∶1,v/v).The SPE eluant was collected,evaporated to near dryness under a gentle nitrogen stream,and dissolved in 100μL n-hexane.The reconstitution in the vial insert was injected into the GC-MS/MS instrument for analysis.The analytes were separated on an Agilent J&W DB-5MS capillary column(30 m×0.25 mm×0.25μm)with temperature programming.The mass spectrometer was operated in the electron ionization(EI)mode.The optimal mass spectrometry conditions were realized by optimizing the instrument parameters such as ion pairs and collision energies.The analytes were detected in the multiple reaction monitoring(MRM)mode,and the internal standard method was used for quantitative analysis.The OCPs and PCBs had good linearities in the range of 0.05-50.0 ng/mL.The limits of detection(LODs,S/N=3)ranged from 1.2 to 71.4 ng/L.The recoveries of the 35 compounds were 72.6%-142%with relative standard deviations(RSDs)of less than 25%at the three spiked levels.The developed SPE-GC-MS/MS method was successfully applied to the simultaneous analysis of OCPs and PCBs in serum samples obtained from the general population in Wuhan.The results showed that the general population in Wuhan was widely exposed to OCPs and PCBs,especially the former.The detection frequencies of eight OCPs and seven PCBs were greater than 50%,and p,p′-DDE,p,p′-DDD,and methoxychlor were detected in all serum sample pools.Non-dioxin-like PCBs(NDL-PCBs)were the dominant PCB congeners,while PCB-28,PCB-153,and PCB-52 were the dominant PCBs in the general population of Wuhan.The concentration of OCPs increased with age.Moreover,the concentration of OCPs in individuals who were more than 66 years old was significantly higher as compared to that in younger individuals.The positive association differing by gender was significant in individuals over 60 years of age.There were no significant differences in PCB concentrations according to gender or age.There were no seasonal differences in the residue levels of OCPs and PCBs in the general population of Wuhan.The developed method is rapid and sensitive;it has the advantages of low limits of detection,satisfactory recoveries,accurate precision,and microsample volume,thus allowing for the simultaneous analysis of trace OCPs and PCBs in microserum samples in epidemiological studies.This robust analytical method also provides a powerful tool for the health risk assessment of OCP and PCB exposure.