基于特征碘离子的非靶向筛查鉴定河北省地下水中碘化消毒副产物

联合高分辨质谱和碘化消毒副产物(I-DBPs)的特征质谱性质, 建立一套完整的非靶向分析方法。以河北省17口监测井为研究对象, 筛查地下水样品中I-DBPs的种类、数量及分布。共筛选出含有同分异构体的I-DBPs疑似离子2408种, 其中不同质荷比的数量为839, 远高于以往研究报道的I-DBPs数量。疑似I-DBPs离子中, 对碘离子响应强度排前十位的离子进行结构鉴定, 其中响应强度排前两位的两种离子被鉴定为酚类I-DBPs, 其发育毒性比对应的脂肪族I-DBPs高数十至数百倍。进一步的分析结果表明, 酚类I-DBPs是样品中主要的I-DBPs 类型之一。最后, 通过主成分分析, 讨论2408种疑似I-DBPs的分布特征。根据主成分分数, 筛选出明显偏离其他采样点的3个采样点。根据装载因子, 通过高斯混合模型对疑似I-DBPs进行聚类, 得到4类离子, 其中3类离子分别属于3个离群采样点的特征污染物。这些结果表明, I-DBPs的分布在河北省内的不同地区具有明显的差异性和复杂性。

Identification of Iodinated Disinfection Byproducts in Groundwaterfrom Hebei Province Using Iodide-Based Nontarget Screening

A complete set of nontargeted analysis method was established by combining the high-resolution MS and the characteristic mass spectrometry properties of iodinated disinfection byproducts (I-DBPs). Groundwater samples were collected from 17 sites in Hebei Province, and an integrated nontarget screening workflow was developed and implemented to identify the category, quantity and distribution of I-DBPs in the groundwater samples. As a result, a total of 2408 suspect I-DBPs ions including isomers were screened, of which 839 unique mass-to-charge ratios were identified, much higher than the numbers reported by previous studies. Among the suspect I-DBPs ions, the structures were carefully analyzed for precursors which were detected with top 10 the most abundant iodide ions in their MS/MS spectra, and the top 2 suspect ions were identified as phenolic I-DBPs, whose developmental toxicity are tens to hundreds of times higher than the corresponding aliphatic DBPs. Further analysis confirmed that the phenolic I-DBPs were one of the main categories of all the I-DBPs detected in samples. Finally, the distribution characteristics of 2408 suspect ions were analyzed based on principal component analysis (PCA). According to the PCA, 3 sites significantly different from other sampling sites were screened as outlier sites. The suspect ions were clustered into 4 classes using Gaussian mixture model according to their loading scores, and ions from 3 of 4 classes were identified as the diagnostic pollutants for 3 outlier sites respectively. The results highlighted the differences and complexity of I-DBPs in groundwater of Hebei Province.