Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, Chang'an University, Xi'an 710054, China.
Int J Environ Res Public Health. 2018 Jul 10;15(7):1458. doi: 10.3390/ijerph15071458.
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 OTC > SD and the binding constant OTC > SD, indicates that HA has a more obvious quenching effect on OTC. The of HA by OTC ranged from 3.223 × 10³ to 12.784 × 10³ L·mol in the range of 298 K to 313 K, while the of HA by SD ranged from 2.051 × 10³ to 5.533 × 10³ L·mol. With the increase of temperature, the quenching constant and binding constant 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 and 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 () was greater than that of SD.
采用三维激发发射矩阵荧光分光光度法研究了腐殖酸（HA）与抗生素的相互作用机制。考察了抗生素浓度、温度和 pH 值对 HA 与抗生素结合强度的影响。结果表明，随着抗生素浓度的增加，对 HA 的猝灭效应增强。土霉素（OTC）和磺胺嘧啶（SD）对 HA 的猝灭均为单一静态猝灭复合物，相互作用力主要为氢键和范德华力。猝灭常数 OTC>SD，结合常数 OTC>SD，表明 HA 对 OTC 的猝灭作用更为明显。OTC 对 HA 的 在 298 K 到 313 K 范围内为 3.223×10³到 12.784×10³L·mol，而 SD 对 HA 的 在 298 K 到 313 K 范围内为 2.051×10³到 5.533×10³L·mol。随着温度的升高，HA 对 OTC 和 SD 的猝灭常数 和结合常数 逐渐减小，低温有利于相互作用。OTC 和 HA 的复合物比 SD 更稳定。在中性碱性条件下，OTC 和 SD 对 HA 的猝灭作用最强，生成的复合物最稳定。但在实验 pH 范围内，OTC 对 HA 的 和 SD 的 均大于 SD，且 OTC 对 HA 猝灭的 pH 效应（）大于 SD。
