多环芳烃(PAHs)及其卤代衍生物(X-PAHs),通常由母体PAHs的光化学和热反应产生,广泛存在于环境中。它们是半挥发性有机化学品(SVOCs),气体/颗粒相之间的分配会影响其环境迁移,转型与命运,这进一步影响了它们对人类的毒性和健康风险。然而,大气颗粒物相(f)的实验分布比缺少大量数据,尤其是X-PAHs.在这项研究中,我们首先检查了53个PAH衍生物的实验f值与其辛醇-空气分配系数(logKOA)之间的相关性,常用于表征有机相中化学物质的分布,并且得到R2=0.803。然后,从M06-2X/6-311+G的分子结构优化中得出的量子化学描述符(d,p)方法进一步用于建立定量结构-性质关系(QSPR)模型。该模型包含两个描述符,平均分子极化率(α)和分子静电势的平衡参数(τ),并且在R2=0.846和RMSE=0.122的情况下产生更好的性能。通过不同策略的机理分析和验证结果证明,该模型可以揭示主导气相和颗粒相之间分布的分子性质,并且可以用于预测其他PAHs/X-PAHs的f值。为其环境生态风险评价提供基础数据。
Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (X-PAHs), which generally produced from photochemical and thermal reactions of parent PAHs, widely exist in the environment. They are semi-volatile organic chemicals (SVOCs) and the partitioning between gas/particulate phases affects their environmental migration, transformation and fate, which further impacts their toxicity and health risk to human. However, there is a large data missing of the experimental distribution ratio in the atmospheric particulate phase (f), especially for X-PAHs. In this
study, we first checked the correlation between experimental f values of 53 PAH derivatives and their octanol-air partitioning coefficients (log KOA), which is frequently used to characterize the distribution of chemicals in organic phase, and yielded R2 = 0.803. Then, quantum chemical descriptors derived from molecular structural optimization by M06-2X/6-311 +G (d,p) method were further employed to develop Quantitative Structure-Property Relationship (
QSPR) model. The model contains two descriptors, the average molecular polarizability (α) and the equilibrium parameter of molecular electrostatic potential (τ), and yields better performance with R2 = 0.846 and RMSE = 0.122. The mechanism analysis and validation results by different strategies prove that the model can reveal the molecular properties that dominate the distribution between gas and particulate phases and it can be used to predict f values of other PAHs/X-PAHs, providing basic data for their environmental ecological risk assessment.