摘要
采用荧光滴定法研究四环素(tetracycline,TC)与太湖溶解性有机质(dissolved organic matter,DOM)和玄武湖DOM的相互作用.三维荧光光谱结合平行因子分析显示,2个湖泊的DOM含有3个荧光组分:类富里酸组分C1、类色氨酸组分C2和类络氨酸组分C3.其中C2的荧光强度远高于C1和C3,是DOM的主要荧光组成.3个荧光组分与TC发生了不同程度的静态猝灭,特别当TC浓度为45.5μmol/L时,类蛋白组分的荧光强度完全被猝灭(100%),并且猝灭作用改变了DOM分子的微环境极性.同步荧光光谱联合二维相关图谱进一步表明类色氨酸组分优先和TC发生猝灭作用,其次为类络氨酸组分和类富里酸组分.Ryan-Weber方程适于拟合DOM与TC的猝灭过程,2个湖泊的DOM中3个荧光组分的络合常数lg K值范围为5.05~5.85,大小顺序为C2>C3>C1.因此,类蛋白组分为主的DOM对TC的络合作用大于类腐殖组分为主的DOM,影响抗生素在湖泊水体中的生物有效性和生态毒性.
Interactions of tetracycline（ TC） with dissolved organic matter（ DOM） collected from Lake Taihu and Lake Xuanwu were investigated through fluorescence quenching. Three fluorescent DOM components,fulvic-（ C1）,tryptophan-（ C2）,and tyrosine-like（ C3） component,were identified in DOM via excitation emission matrix spectra with parallel factor analysis（ EEMPARAFAC）. Results from fluorescence quenching titration showed that the fluorescence of 3 components was quenched at different degree by TC through static quenching. When the TC concentration increased to 45.5 μmol/L,the whole florescence of C2 and C3 were almost quenched,while 20% of C1 fluorescence was inaccessible. The quenching also induced conformational changes in DOM molecules. Synchronous fluorescence spectra combined with two dimensional correlation spectroscopy（ 2 D-COS） further revealed that the complexation firstly occurred for tryptophan-like substance,followed by tyrosine-and fulvic-like substance. The associated complexing constants（ lg K） of 3 components with TC were in the range of 5.05-5.85,followed the order of C2 C3 C1. The strong binding ability of protein-like substances confirmed their prominent role in the TC-DOM complexation. These results highlight the significant impact of DOM on the bioavailability and ecotoxicity of antibiotics in freshwater lakes.
作者
曹驰程
王友权
章奇
张晖
CAO Chicheng;WANG Youquan;ZHANG Qi;ZHANG Hui(： Key Laboratory of Environmental Medicine Engineering,Ministry of Education,School of Public Health,Southeast Uni versity,Nanjing 210009,P.R.China;： Key Laboratory of Environmental Engineering of Jiangsu Province,College of Biology and the Environment,Nanjing For estry University,Nanjing 210037,P.R.China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2018年第4期1004-1011,共8页
Journal of Lake Sciences
基金
东南大学通识课程项目(1125000131)
中央高校基本科研业务费资助项目(2242017K40041)联合资助
