Rate constants of hydroxyl radicals reaction with different dissociation species of fluoroquinolones and sulfonamides: Combined experimental and QSAR studies

Xiang Luo; Xiaoxuan Wei; Jingwen Chen; Qing Xie; Xianhai Yang; Willie J G M Peijnenburg

doi:10.1016/j.watres.2019.115083

Rate constants of hydroxyl radicals reaction with different dissociation species of fluoroquinolones and sulfonamides: Combined experimental and QSAR studies

Water Res. 2019 Dec 1:166:115083. doi: 10.1016/j.watres.2019.115083. Epub 2019 Sep 14.

Authors

Xiang Luo¹, Xiaoxuan Wei², Jingwen Chen³, Qing Xie¹, Xianhai Yang⁴, Willie J G M Peijnenburg⁵

Affiliations

¹ Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
² Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China; College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, 321004, China.
³ Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China. Electronic address: jwchen@dlut.edu.cn.
⁴ Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China; Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
⁵ Institute of Environmental Sciences (CML), Leiden University, Leiden, 2300, RA, the Netherlands; National Institute of Public Health and the Environment (RIVM), Center for Safety of Substances and Products, Bilthoven, 3720, BA, the Netherlands.

PMID: 31541794
DOI: 10.1016/j.watres.2019.115083

Abstract

Hydroxyl radicals (·OH) initiated degradation is an important process governing fate of aquatic organic micropollutants (OMPs). However, rate constants for aqueous reaction of OMPs with ·OH (k_OH) are available only for a limited number of OMPs, which complicates fate assessment of OMPs. Furthermore, molecular structures of many OMPs contain ionizable groups, and the OMPs may dissociate into different anionic/cationic species with different reactivity towards ·OH. Therefore, it is of importance to determine k_OH of ionizable OMPs, and to develop quantitative structure-activity relationship (QSAR) models for predicting k_OH of OMPs at different ionization forms. Herein k_OH values of 9 fluoroquinolones (FQs) and 11 sulfonamides (SAs) at 3 dissociation forms (FQ^±/FQ⁺/FQ^-, SA⁰/SA⁺/SA^-) were determined by competition kinetics experiments. A QSAR model using theoretical molecular structural descriptors was subsequently developed. The QSAR model successfully corroborated previous experimental results, exhibited good statistical performance, and is capable to predict k_OH for FQs and SAs with different dissociation forms at environmentally relevant pH conditions. As organic ions have rarely been included in previous QSAR studies, the newly developed model that covers both neutral molecules and ions is of significance for future QSAR development as well as fate assessment of ionizable OMPs.

Keywords: Antibiotics; Dissociation forms; Hydroxyl radicals; Quantitative structure-activity relationship (QSAR); Reaction rate constants.

MeSH terms

Fluoroquinolones
Hydroxyl Radical*
Quantitative Structure-Activity Relationship
Sulfonamides
Water Pollutants, Chemical*

Substances

Fluoroquinolones
Sulfonamides
Water Pollutants, Chemical
Hydroxyl Radical