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In this study, the interaction between the humus and two antibiotics was studied by UV-Vis spectroscopy to describe the interaction mechanism and the effects of different environmental factors on the mechanism. Results showed that humic acid (HA) containing more aromatic groups was easily associated with antibiotics. In the HA-OTC, with the increase of the concentration of OTC, there were obvious absorption peaks in the 230–260 nm and 330–360 nm range, and the absorption band of the HA ultraviolet spectrum underwent a slight blue shift and the absorption intensity increased, demonstrating that a new ground state complex was generated. In the HA-SD, with the increase of SD concentration, an aromatic structure absorption peak appeared in the 190–220 nm range, and the peak value increased and the absorption band underwent a red shift, and the aromatization of HA decreased, which enhanced the interaction between the antibiotics and HA. With the increase of pH, the absorption band of HA, HA-OTC and HA-SD ultraviolet spectrum suffered a blue shift, the degree of polymerization of HA molecules decreased, and the number of adsorption binding sites increased, which resulted in the interaction of HA with antibiotics being enhanced. The absorption band of HA, HA-OTC and HA-SD displayed a red shift with the increase of ionic strength, which indicated that the repulsion within HA particles was weakened, and the molecular polymerization was strengthened and therefore, the interaction between antibiotics and HA was inhibited. The UV characteristics of the HA, HA-OTC and HA-SD systems were insensitive to the temperature. This study lays the foundation for better studying the effect of humus on the distribution of antibiotic residues in the environment.
Xiaoyu Yuan; Shengke Yang; Jie Fang; Xueli Wang; Haizhen Ma; Zongzhou Wang; Runze Wang; Yaqian Zhao. Interaction Mechanism between Antibiotics and Humic Acid by UV-Vis Spectrometry. International Journal of Environmental Research and Public Health 2018, 15, 1911 .
AMA StyleXiaoyu Yuan, Shengke Yang, Jie Fang, Xueli Wang, Haizhen Ma, Zongzhou Wang, Runze Wang, Yaqian Zhao. Interaction Mechanism between Antibiotics and Humic Acid by UV-Vis Spectrometry. International Journal of Environmental Research and Public Health. 2018; 15 (9):1911.
Chicago/Turabian StyleXiaoyu Yuan; Shengke Yang; Jie Fang; Xueli Wang; Haizhen Ma; Zongzhou Wang; Runze Wang; Yaqian Zhao. 2018. "Interaction Mechanism between Antibiotics and Humic Acid by UV-Vis Spectrometry." International Journal of Environmental Research and Public Health 15, no. 9: 1911.
The method of Three-Dimensional Excitation Emission Matrix Fluorescence Spectrophotometer was used to identify the interaction mechanism between humic acid (HA) and antibiotics. The effects of antibiotic concentration, temperature, and pH on the bonding strength between HA and antibiotics were investigated. The results showed that with the increase of antibiotics concentration, the quenching effect on HA was enhanced. The quenching of HA by both oxytetracycline (OTC) and sulfadiazine (SD) is a single static quenching of the complexes, and the interaction forces are mainly a hydrogen bond and the van der Waals force. The quenching constant KsvOTC > KsvSD and the binding constant KbOTC > KbSD, indicates that HA has a more obvious quenching effect on OTC. The Kb of HA by OTC ranged from 3.223 × 103 to 12.784 × 103 L·mol−1 in the range of 298 K to 313 K, while the Kb of HA by SD ranged from 2.051 × 103 to 5.533 × 103 L·mol−1. With the increase of temperature, the quenching constant Ksv and binding constant Kb of both OTC and SD by HA gradually decrease, and the low temperature is beneficial to the interaction. The composite of OTC and HA is more stable than SD. Under neutral alkaline conditions, both OTC and SD had the strongest quenching effect on HA, and the resulting complex was the most stable. However, the Ksv and Kb of HA by OTC were greater than SD in the pH range of the experiment and the pH effect on quenching of HA by OTC (Ksv) was greater than that of SD.
Runze Wang; Shengke Yang; Jie Fang; Zongzhou Wang; Yangyang Chen; Dan Zhang; Chunyan Yang. Characterizing the Interaction between Antibiotics and Humic Acid by Fluorescence Quenching Method. International Journal of Environmental Research and Public Health 2018, 15, 1458 .
AMA StyleRunze Wang, Shengke Yang, Jie Fang, Zongzhou Wang, Yangyang Chen, Dan Zhang, Chunyan Yang. Characterizing the Interaction between Antibiotics and Humic Acid by Fluorescence Quenching Method. International Journal of Environmental Research and Public Health. 2018; 15 (7):1458.
Chicago/Turabian StyleRunze Wang; Shengke Yang; Jie Fang; Zongzhou Wang; Yangyang Chen; Dan Zhang; Chunyan Yang. 2018. "Characterizing the Interaction between Antibiotics and Humic Acid by Fluorescence Quenching Method." International Journal of Environmental Research and Public Health 15, no. 7: 1458.