Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, PR China.
Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
Environ Sci Technol. 2024 Jul 2;58(26):11685-11694. doi: 10.1021/acs.est.4c01936. Epub 2024 Jun 21.
A regular tetrahedron model was established to pierce the fractionation of dissolved organic matter (DOM) among quaternary components by using high-resolution mass spectrometry. The model can stereoscopically visualize molecular formulas of DOM to show the preference to each component according to the position in a regular tetrahedron. A classification method was subsequently developed to divide molecular formulas into 15 categories related to fractionation ratios, the relative change of which was demonstrated to be convergent with the uncertainty of mass peak area. The practicality of the regular tetrahedron model was verified by seven kinds of sludge from waste leachate treatment and sewage wastewater treatment plants by using stratification of extracellular polymeric substances coupled with Orbitrap MS as an example, presenting the DOM chemodiversity in stratified sludge flocs. Sensitivity analysis proved that classification results were relatively stable with the perturbation of four model parameters. Multinomial logistic regression analysis could further help identify the effect of molecular properties on the fractionation of DOM based on the classification results of the regular tetrahedron model. This model offers a methodology for the assessment of specificity of sequential extraction on DOM from solid or semisolid components and simplifies the complex mathematical expression of fractionation coefficients for quaternary components.
采用高分辨质谱建立了一个规则四面体模型，以穿透季元素之间溶解有机物（DOM）的分馏。该模型可以立体可视化 DOM 的分子公式，根据规则四面体中的位置显示对每个成分的偏好。随后开发了一种分类方法，将分子公式分为 15 类，与分馏比有关，其相对变化与质量峰面积的不确定性表现出收敛性。通过将细胞外聚合物的分层与轨道阱 MS 相结合，以垃圾渗滤液处理和污水废水处理厂的七种污泥为例，验证了规则四面体模型的实用性，展示了分层污泥絮体中的 DOM 化学多样性。敏感性分析证明，分类结果在四个模型参数的干扰下相对稳定。多项逻辑回归分析可以进一步帮助根据规则四面体模型的分类结果确定分子特性对 DOM 分馏的影响。该模型为评估从固体或半固体成分中提取 DOM 的顺序提取的特异性提供了一种方法，并简化了季元素分馏系数的复杂数学表达式。
