典型可溶有机质与磺胺二甲嘧啶的络合作用研究

以藻源有机质(AOM)和腐殖酸(HA)作为典型生物大分子可溶有机质(DOM)和腐殖化DOM,采用荧光猝灭滴定和光谱分析考察磺胺二甲嘧啶(SMZ)与DOM的络合作用.三维荧光光谱结合平行因子分析显示AOM荧光组分主要由类酪氨酸和类色氨酸物质组成,而类富里酸和类腐殖酸物质是HA荧光组分的主要构成.4种荧光组分可与SMZ发生不同程度的静态猝灭,且猝灭过程中DOM分子构象改变.同步荧光光谱结合二维相关图谱进一步发现类酪氨酸优先于类色氨酸组分与SMZ发生络合作用.Ryan-Weber非线性模拟拟合表明AOM中各荧光组分与SMZ的络合稳定常数(logK)大小为:类富里酸(3.33)类酪氨酸(3.12)类色氨酸(2.15)类腐殖酸(1.57);而HA中大小为:类富里酸(3.06)类腐殖酸(2.02).总体上生物大分子DOM对SMZ的亲和力高于腐殖化DOM.DOM与SMZ的相互作用可改变水环境中抗生素的形态和归趋,影响其生物有效性和生态毒性.

Complexation of sulfamethazine with typical dissolved organic matter

Complexations of sulfamethazine (SMZ) with algae-derived dissolved organic matter (AOM) and humic acid (HA) were investigated using fluorescence quenching titration with multi-spectroscopic techniques. Excitation emission matrix spectra with parallel factor analysis indicates that tyrosine-and tryptophan-like components were the dominated fluorescent components in AOM, whereas HA was mainly composed of fulvic acid-and humic acid-like fluorescent components. Results from fluorescence quenching show that the four components were quenched at different degree by SMZ through static quenching, inducing conformational changes in DOM fractions. Synchronous fluorescence spectra combined with two dimensional correlation spectroscopy further reveals that the complexation firstly occurred for tyrosine-like substances, followed by tryptophan-like substances. The conditional stability constants (logK) obtained by Ryan-Weber equation were in the order of fulvic acid-(3.33) > tyrosine-(3.12) > tryptophan-(2.15) > humic acid-like (1.57) components in AOM, and fulvic acid-(3.06) > humic acid-like (2.02) components in HA. These results indicate that the binding affinity of biomacromolecules DOM to SMZ was generally larger than that of humic DOM. The strong interaction between SMZ and DOM may regulate the existence, mobility, and bioavailability of antibiotics and eventually change their ecotoxicity in aquatic environments.