哈尔滨市降雪中溶解性有机物光谱特性分析

研究雨雪中的溶解性有机物(DOM)将有利于把握其理化性质及其在生态系统中的行为和功能.本研究运用三维荧光光谱(EEMs)技术结合平行因子分析(PARAFAC)、紫外-可见光谱技术(UV-vis),对哈尔滨市2018年3月1日降雪样品中DOM的光谱特性及来源进行解析.结果表明,降雪样品中DOM的相对分子质量较大,芳香构造程度较高,C=C不饱和双键结构较多,腐殖化程度更高,结构更复杂,芳环上含氧官能团含量较少,有机质疏水性较强;EEMs结合PRAFAC解析出3种组分,分别为类腐殖质类物质(C₁和C₂)和类色氨酸(C₃),荧光特征参数(荧光指数FI、自生源指数BIX、腐殖化系数HIX_b和新鲜指数β∶α)表明,降雪样品中DOM受陆源和生物源同时作用,腐殖化程度较高且受到陆源影响严重,自生源组分较少,新生成的DOM比例较低.

Spectroscopic characterization analysis of dissolved organic matter in snow samples from Harbin

The study of dissolved organic matter(DOM) in rain and snow will help to understand its physic-chemical properties and its behavior and function in ecosystem. In this study, three-dimensional fluorescence spectroscopy(EEMs) combined with parallel factor analysis(PARAFAC) and UV-vis spectroscopy(UV-vis) were used to analyze the spectral characteristics and origin of DOM in snow samples from Harbin City on march 1 st, 2018. The results showed that the relative molecular weight of DOM in snow samples was larger. The aromatic structure was higher and the C=C unsaturated double bond structure was more. The humification degree was higher and the structure was more complex. The content of oxygen functional groups on the aromatic ring was less and the hydrophobicity of organic matter was stronger. EEMs combined with PRAFAC produced a three-component model: humic-like substances(C₁ and C₂) and tryptophan-like substances(C₃). Fluorescence characteristic parameters(fluorescence index FI, authigenic source index BIX, humic coefficient HIX_b, fresh index β∶α) showed that DOM in snow samples was affected by both terrestrial and biological sources. The degree of humification was higher and severely affected by terrestrial sources.