雨水中溶解有机质的光谱学研究

Spectroscopic Characterization of Dissolved Organic Matter Isolated from Rainwater

  • 摘要: 利用紫外-可见吸收光谱(UV-Vis)和荧光激发-发射矩阵光谱(EEMs)技术研究了广州市番禺区大学城雨水中溶解有机质(DOM)的吸收和荧光等光谱特性. 结果表明:不同气候特征的雨水DOM的吸收光谱随波长增加呈指数衰减,UV-Vis光谱的斜率指数S的变化表明不同季节DOM 的相对分子量不同:夏季DOM平均相对分子量较高,而春季和冬季DOM相对分子量相对较低.雨水中DOM的EEMs光谱表明样品中存在3个类腐殖质峰:紫外类腐殖质峰A、海洋类腐殖质峰M和类蛋白(色氨酸)峰T,其中紫外类腐殖质峰A 在雨水DOM中占主导作用. 另外腐殖化指数(HIX)表明冬季雨水样品的腐殖化程度较高.

     

    Abstract: The dissolved organic matter (DOM) in rainwater were collected from universities town of Guangzhou and were characterized with UV-Vis absorbance and three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopies. The results shown that the UV-Vis absorbance spectra exhibited similar characteristics, which was exponential attenuation with the increasing wavelength. The spectral slope coefficient (S) of UVvisible spectra indicated relative higher molecular weight in summer than that in spring and winter. Three fluorophores were identified in the EEM fluorescence spectra of DOM: The UV humic-like peak A, the marine humic-like peak M and the protein-like peak (tryptophan) T, and the humic-like peak A was the dominant component in the rain DOM in Guangzhou. Humification index (HIX) suggested that the rain DOMs in winter were characterized with relatively high humification degree.

     

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