长江江苏段新污染物非靶向识别研究

Nontarget Screening of Emerging Contaminants in Jiangsu Section of Yangtze River

随着城市化和工业化的发展,越来越多的化学品被大量生产和广泛使用,并通过污水排放、农业排水等形式进入水环境。为全面筛查长江下游江苏段的潜在新污染物,本研究提出了基于高效液相色谱和飞行时间质谱的谱库检索耦合分子网络的非靶向筛查策略,利用精确质量数、同位素分布和二级质谱碎片信息进行质谱库匹配,共识别出118种新污染物,涉及杀虫剂、除草剂、杀菌剂、抗生素、持久性有机污染物、阻燃剂、塑化剂、表面活性剂、化工中间体等多种类别。通过分子网络技术进一步鉴定与已注释污染物结构相似的未被注释的化学物质;通过标准品验证确证了23种污染物;定量分析结果表明,全氟化合物以及药物与个人护理品普遍存在于水体中。谱库检索耦合分子网络的非靶向筛查策略能够在无先验信息和标准品的情况下高通量鉴定水体污染物,并利用已注释物质对谱库未注释特征峰进行结构推断,加快水环境中新型与未知污染物的系统化发现。

With the development of urbanization and industrialization,more and more chemicals were produced in large quantities and widely used.As a result,they entered the water environment through sewage discharge and agricultural drainage.Currently,the analytical methods of contaminants in water include three main strategies,including target screening,suspect analysis and nontarget screening.The number of compounds identified using target screening methods has increased to hundreds,which is far from meeting the current demand for emerging contaminants(ECs)detection in water environment.To comprehensively screen potential emerging contaminants in the Yangtze River in Jiangsu Province,a nontarget screening strategy combined spectral library search with a molecular network was proposed in Jiangsu-Anhui provincial boundary cross section and 22 drinking water sources in Jiangsu section of Yangtze River.Under this strategy,through spectral library screening using a in-house library,a total of 118 emerging contaminants were identified by accurate mass,isotope distribution and MS/MS fragment ions.These contaminants involved pesticides,herbicides,fungicides,drugs,antibiotics,persistent organic pollutants,flame retardants,plasticizers,indicated active agents,chemical intermediates,and other categories.Since traditional targeted screening relies on commercial standards and screening lists,nontarget screening is a more favorable approach to study ECs and their transformation products in water.Therefore,unannotated chemical substances with similar structures to known contaminants were identified through molecular network technology based on the premise that structurally similar compounds have similar fragment ions.Through using the Global Natural Products Society molecular network(GNPS)to extract molecular families,another contaminant with similar toxicity to amantadine,N-methyl-1-adamantaneamine was found.Furthermore,twenty-three contaminants were confirmed through commercial standard,and 14 of them were detected at a rate of 100%.The quantitative analysis revealed the prevalence of perfluorinated compounds,pharmaceuticals,and personal care products in water bodies,and the total concentrations of the 23 contaminants in each sample ranged from 6.46×102 ng/L to 1.72×103 ng/L.Seven drugs and personal care products were detected.Amantadine was detected at the highest concentration among all locations,and perfluorooctanoic acid(PFOA),amantadine and 2,4-dinitrophenol were detected with the highest mean concentration levels in each location.The nontarget screening strategy using spectral library search and molecular network enabled high-throughput identification of contaminants in water without prior information and standards,in which the structures of unannotated characteristic peaks were inferred from annotated substances with spectral libraries.This strategy will accelerate the systematic discovery of emerging and unknown contaminants in the aqueous environment.