不同pH 值下环丙沙星的形态分布及光解研究

不同pH 值下环丙沙星的形态分布及光解研究
尉小旋 ，陈景文*
，乔显亮，葛林科，张思玉
工业生态与环境工程教育部重点实验室，大连理工大学环境学院，116024，大连
E-mail: jwchen@
光化学转化是影响天然水中抗生素环境归趋的重要因素。

考察了氟喹诺酮类抗生素环丙沙星(ciprofloxacin, CIP)在不同pH 值条件下的形态分布和光化学反应动力学。

环丙沙星的光解在pH = 2.0~12.0范围内先加快后减慢，在pH = 8左右最快。

采用UV-vis 滴定与正定矩阵因子分解相结合的方法得到了不同形态环丙沙星的UV-vis 光谱及光解量子产率。

当λ < 315 nm 时，随pH 增大环丙沙星的吸光光谱发生蓝移，而当λ > 315 nm 时，其吸收光谱发生红移。

不同形态环丙沙星的光解量子产率具有明显差异(p < 0.05)，导致其光解速率差异较大。

中性分子的光解量子产率最大，光解最快，其次是碱性分子和酸性分子。

O N
F
N
N O
HO
H
k a, 1
k a, 2
k a, 3
k a, 4
H 4
CIP H 3
CIP H 2
CIP HCIP CIP -a, 4
k /m i n -1
pH
Fig. 1 Structure and protonation states of CIP.
Fig. 2 pH dependence of CIP photolysis rate. Error bars
represent the 95% confidence interval (n = 3).
关键词：环丙沙星；pH 值；解离形态；光解。

感谢国家重点基础研究专项(973)基金(2006CB403302)和国家自然科学基金(20777010)资助
参考文献：
[1] Larsson D G J, De Pedro C, Paxeus N. J Hazard Mater, 2007, 148(3):751-755.
[2] Ge L K, Chen J W, Qiao X L, Lin J, Cai X Y . Environ Sci Technol, 2009, 43(9):3101-7.
[3] Ge L K, Chen J W, Wei X X, Zhang S Y, Qiao X L, Cai X Y, Xie Q. Environ Sci Technol, 2010, doi: 10.1021/es902852v.
Study on the Speciation and Photodegradation of Ciprofloxacin at
Different pH Values
Xiao-Xuan Wei, Jing-Wen Chen,*
Xian-Liang Qiao, Lin-Ke Ge, Si-Yu Zhang Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology,
116024, Dalian
Photodegradation plays a central role in determining the environmental fate of antibiotics in natural waters. The pH dependence of ciprofloxacin (CIP) protonation states and photolysis was investigated. The photolysis rate of CIP was increased from pH 2 to 8 and decreased from pH 8 to 12. The UV-vis absorption spectra and the photodegradation quantum yield (Φ) of each protonation state were obtained by the method of UV-vis titration combined positive definite matrix factorization (PMF). The maximum absorption of CIP at λ < 315 nm was blue shifted and at λ > 315 nm was red shifted with pH increasing. Φ of CIP at different speciation varied significantly, leading to totally different photolysis rate. Neutral form degrades the fastest
with the largest Φ, followed by anionic form and cationic form.
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