基于GC×GC-TOF MS对太湖流域水体中有机物的非靶标识别

Non-target Identification of Organic Compounds in Water of Taihu Lake Based on GC×GC-TOF MS

本研究基于全二维气相色谱-飞行时间质谱(GC×GC-TOF MS),采用非靶标筛选法分析太湖流域18个采样点的水样,通过特征离子峰、精确质量数、保留指数偏差和NIST谱库匹配,共识别出466种有机物,其中各采样点共有检出率超过80%的化合物有68种,主要是香精香料、工业化学品和多用途化合物,并识别出多种尚未纳入监管清单的化合物,如顺式-11-二十烯酰胺、地塞诺和γ-谷甾醇。对非靶标方法识别的化合物进行半定量计算,发现各类化合物的单体浓度在0.025~113.145μg/L之间波动,其中浓度较高的是顺式-11-二十烯酰胺、邻苯二甲酸二丁酯和地塞诺。通过聚类分析发现,新塘港和小梅口点位的水体污染较轻,主要受涂料行业排放的影响,其余采样点位污染较重,主要受工业和食品加工业的影响。此外,本研究还对检出的68种有机物的半定量浓度进行初步的生态风险评估,发现有22种污染物具有中等以上生态风险,其中的11种污染物具有高生态风险,这为评估水体有机物健康效应提供了参考。

Organic pollutants are often enriched in rivers and lakes,which significantly affect human health.In this study,water samples from 18 sampling sites in the Taihu Lake basin were analyzed using a non-targeted screening method based on two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GC-TOF MS).A total of 466 organic compounds were identified by the characteristic ions,accurate mass to charge ratio,retention index deviation and the NIST spectral library,of which 68 compounds were detected at more than 80% across the sampling sites,mainly attributed to flavors and fragrances products,industrial chemicals and multi-purpose compounds.Moreover,a number of compounds not yet included in the regulatory list were identified,such as cis-11-eicosanoids,dextran and gamma-sitosterol.Semi-quantitative calculations of the compounds identified by the non-targeting method revealed that the concentrations of single compound fluctuated within 0.025-113.145 μg/L.The higher concentrations were found for cis-11-eicosenamide,dibutyl phthalate and dextranol.Cluster analysis revealed that the water at the Xintang Port and Xiaomeikou sites were less polluted and were mainly influenced by emissions from the paint industry,while the remaining sampling sites were more polluted and mainly influenced by industry and food manufacturing industries.In addition,the ecological risk assessment based on the semi-quantitative concentrations of 68 detected organic compounds was conducted in this study.The results indicateed that 22 pollutants were exhibited with moderate or higher ecological risk,and 11 of them were of high ecological risk,providing some references for assessing the health effects of organics in water.In summary,the non-target analysis in this study can quickly and accurately identify a large number of organics in water.Compared with the quantitative target analysis,the non-targeted analysis provides a rapid and comprehensive map for the distribution of water pollutants,which is important for determining the characteristics of the main pollutants in unknown waters and directing further analysis and assessment of water pollution.