Effect of dissolved organic matter on pre-equilibrium passive sampling: A predictive QSAR modeling study

Wei Lin; Ruifen Jiang; Yong Shen; Yaxin Xiong; Sizi Hu; Jianqiao Xu; Gangfeng Ouyang

doi:10.1016/j.scitotenv.2018.04.116

Effect of dissolved organic matter on pre-equilibrium passive sampling: A predictive QSAR modeling study

Sci Total Environ. 2018 Sep 1:635:53-59. doi: 10.1016/j.scitotenv.2018.04.116. Epub 2018 Apr 13.

Authors

Wei Lin¹, Ruifen Jiang², Yong Shen¹, Yaxin Xiong¹, Sizi Hu¹, Jianqiao Xu¹, Gangfeng Ouyang³

Affiliations

¹ MOE Key Laboratory of Aquatic Product Safety, KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China.
² Guangzhou Key Laboratory of Environmental Exposure and Health, Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China. Electronic address: jiangrf5@jnu.edu.cn.
³ MOE Key Laboratory of Aquatic Product Safety, KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China. Electronic address: cesoygf@mail.sysu.edu.cn.

PMID: 29660727
DOI: 10.1016/j.scitotenv.2018.04.116

Abstract

Pre-equilibrium passive sampling is a simple and promising technique for studying sampling kinetics, which is crucial to determine the distribution, transfer and fate of hydrophobic organic compounds (HOCs) in environmental water and organisms. Environmental water samples contain complex matrices that complicate the traditional calibration process for obtaining the accurate rate constants. This study proposed a QSAR model to predict the sampling rate constants of HOCs (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides) in aqueous systems containing complex matrices. A homemade flow-through system was established to simulate an actual aqueous environment containing dissolved organic matter (DOM) i.e. humic acid (HA) and (2-Hydroxypropyl)-β-cyclodextrin (β-HPCD)), and to obtain the experimental rate constants. Then, a quantitative structure-activity relationship (QSAR) model using Genetic Algorithm-Multiple Linear Regression (GA-MLR) was found to correlate the experimental rate constants to the system state including physicochemical parameters of the HOCs and DOM which were calculated and selected as descriptors by Density Functional Theory (DFT) and Chem 3D. The experimental results showed that the rate constants significantly increased as the concentration of DOM increased, and the enhancement factors of 70-fold and 34-fold were observed for the HOCs in HA and β-HPCD, respectively. The established QSAR model was validated as credible (R_Adj.²=0.862) and predictable (Q²=0.835) in estimating the rate constants of HOCs for complex aqueous sampling, and a probable mechanism was developed by comparison to the reported theoretical study.

Main finding of the work: The present study established a QSAR model of passive sampling rate constants and calibrated the effect of DOM on the sampling kinetics.

Keywords: Complex matrix effects; Flow-through system; Hydrophobic organic compounds (HOCs); Passive sampling; Quantitative structure-activity relationship (QSAR); Rate constants.

MeSH terms

Humic Substances / analysis*
Kinetics
Models, Chemical
Quantitative Structure-Activity Relationship*
Water Pollutants, Chemical / analysis*

Substances

Humic Substances
Water Pollutants, Chemical