title: Kinetics and thermodynamics of interaction between sulfonamide antibiotics and humic acids: Surface plasmon resonance and isothermal titration microcalorimetry analysis.
abstract: The presence of sulfonamide antibiotics in the environments has been recognized as a crucial issue. Their migration and transformation in the environment is determined by natural organic matters that widely exist in natural water and soil. In this study, the kinetics and thermodynamics of interactions between humic acids (HA) and sulfamethazine (SMZ) were investigated by employing surface plasmon resonance (SPR) combined with isothermal titration microcalorimetry (ITC) technologies. Results show that SMZ could be effectively bound with HA. The binding strength could be enhanced by increasing ionic strength and decreasing temperature. High pH was not favorable for the interaction. Hydrogen bond and electrostatic interaction may play important roles in driving the binding process, with auxiliary contribution from hydrophobic interaction. The results implied that HA existed in the environment may have a significant influence on the migration and transformation of organic pollutants through the binding process.
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Xu
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Han-Qing
authors.initials: HQ
authors.lastname: Yu
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China. Electronic address: gpsheng@ustc.edu.cn.
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Sheng
mesh_terms: D002151:Calorimetry; D004785:Environmental Pollutants / Q000737:chemistry*; D006812:Humic Substances; D007700:Kinetics; D013449:Sulfonamides / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D013816:Thermodynamics
chemical_list: D004785:Environmental Pollutants; D006812:Humic Substances; D013449:Sulfonamides
keywords: Humic substances; Isothermal titration microcalorimetry (ITC); Sulfonamide; Surface plasmon resonance (SPR)