State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
J Environ Sci (China). 2009;21(5):581-8. doi: 10.1016/s1001-0742(08)62311-6.
With XAD-series and ion exchange resins, dissolved organic matter (DOM) from Lake Hongfeng in Southwestern China Plateau was isolated into 6 fractions, i.e., humic acid (HA), fulvic acid (FA), hydrophobic neutrals (HON), hydrophilic acids (HIA), hydrophilic bases (HIB) and hydrophilic neutrals (HIN). Those fractions were characterized by high performance size exclusion chromatography, fluorescence spectroscopy and UV absorbance. Among the 6 fractions, FA was predominant and accounted for 51% of the total DOM. The weight-average (Mw) and number-averaged (Mn) molecular weight of these fractions ranged from 1688 to 2355 Da and from 1338 to 1928 Da, respectively. A strong correlation was observed between specific UV absorbance at 280 nm, E2/E3 (absorbance at 250 nm to 365 nm), and the molecular weight for DOM fractions. UV-Vis fulvic-like fluorescence peaks were found in all fractions. Protein-like fluorescence peaks existed in HON may indicate that microbial activity was severely in Lake Hongfeng. There was a significant relationship between fluorescence intensities and specific UV absorbance at 254 nm for those DOM fractions, suggesting their similar luminescence characteristics. The values of fluorescence index (f450/500) indicated that hydrophobic fractions may derive from terrestrial sources, and the hydrophilic fractions from microbial and terrestrial origins. Those results suggest that there were inter-relationships between molecular weight, fluorescence and absorbance characteristics, and also subtle consistencies between the hydrophilic and hydrophobic properties and the sources for these 6 fractions from Lake Hongfeng.
采用 XAD 系列和离子交换树脂，从中国西南高原红枫湖中分离得到 6 种溶解有机质（DOM）组分，分别为腐殖酸（HA）、富里酸（FA）、疏水性中性物（HON）、亲水性酸（HIA）、亲水性碱（HIB）和亲水性中性物（HIN）。利用高效体积排阻色谱、荧光光谱和紫外吸光度对这些组分进行了表征。在这 6 种组分中，FA 是主要组分，占总 DOM 的 51%。这些组分的重均（Mw）和数均（Mn）分子量范围分别为 1688-2355 Da 和 1338-1928 Da。DOM 各组分的特征参数（如 280nm 处的紫外吸光度、E2/E3（250nm-365nm 处的吸光度）与分子量之间存在很强的相关性。所有组分均检测到富里酸样紫外可见荧光峰，HON 中存在蛋白质样荧光峰，可能表明红枫湖中微生物活性较强。DOM 各组分的荧光强度与 254nm 处的紫外吸光度之间存在显著相关性，表明它们具有相似的发光特性。荧光指数（f450/500）的值表明，疏水性组分可能来源于陆源，而亲水性组分可能来源于微生物和陆源。这些结果表明，分子量、荧光和吸光度特征之间存在相互关系，并且这些组分的亲水性和疏水性以及来源之间存在微妙的一致性。
