| 超滤、三维荧光光谱与高效体积排阻色谱联合表征地表水环境中溶解有机质的性质 |
| 摘要点击 2935 全文点击 2076 投稿时间：2007-11-07 修订日期：2007-12-10 |
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| 中文关键词 溶解有机质 超滤 荧光光谱 高效体积排阻色谱 |
| 英文关键词 dissolved organic matter ultrafiltration fluorescence high-performance size-exclusion chromatography |
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| 中文摘要 |
| 超滤、三维荧光光谱以及高效体积排阻色谱3种研究方法的结合可以表征不同类型荧光物质的相对分子质量分布规律，进而揭示它们的来源以及组分差异.用截留相对分子质量为1 000的再生纤维素超滤膜对几种不同类型地表水体中的溶解有机质进行分离后，利用三维荧光光谱以及相对分子质量分布特征谱图表征超滤完成后滞留液中相对分子质量较高的组分和渗透液中相对分子质量较低的组分中溶解有机质的性质.结果发现，湖北神农架大九湖沼泽水中原先被强腐殖酸荧光吸收峰E(Ex/Em: 360 nm/462 nm)掩盖的类富里酸荧光吸收峰A(Ex/Em: 260 nm/450 nm)和C(Ex/Em: 320 nm/439 nm)以及类蛋白荧光吸收峰B(Ex/Em: 275 nm/312 nm)和D(Ex/Em: 220 nm/308 nm)因其相对分子质量较小而被分离进入渗透液中，可被荧光检测；贵州红枫湖南湖内源产生的类蛋白荧光吸收峰B(Ex/Em: 280 nm/334 nm)和D(Ex/Em: 225 nm/328 nm)在原水中含量太低，即使采用灵敏度高的荧光检测手段也很难从原水中直接鉴别出来，但超滤后却因其相对分子质量大而被保存在超滤滞留液中.此外，研究还发现不同来源的类富里酸荧光物质和类蛋白荧光物质其相对分子质量大小也存在差异.如红枫湖南湖内源产生的类蛋白荧光物质具有较大的相对分子质量分布，被保存在超滤滞留液中；而贵州阿哈湖外源输入的类蛋白荧光物质相对分子质量则较小，易通过超滤膜进入渗透液中.因此， 3种研究方法的联合可以为研究地表水体中溶解有机质的性质提供方便直接的定性信息. |
| 英文摘要 |
| The combination of ultrafiltration, three-dimensional excitation/emission matrix (3DEEM) fluorescence spectroscopy and high-performance size-exclusion chromatography (HPSEC) was used to characterize the molecular weight distribution properties of different fluorescence materials, further revealing the differences in the sources and components. Dissolved organic matter (DOM) from different lakes fractionated by ultrafiltration with a nominal 1 000 molecular weight cut-off regenerated cellulose membrane, then 3DEEM spectrophotometry and HPSEC were applied to investigate the characteristics of high molecular weight materials in retentate and low molecular weight materials in permeate. The result indicated that the fulvic acid-like (Ex/Em≈260 nm/450 nm of peak A and Ex/Em≈320 nm/439 nm of peak C) and protein-like (Ex/Em≈275 nm/312 nm of peak B and Ex/Em≈220 nm/308 nm of peak D) fluorophores in permeate were detected after ultrafiltration which is covered by high absorbing peak of humic-like (Ex/Em≈360 nm/462 nm of peak E) fluorescence fluorophores in the original Shennongjia bog water, Hubei province. They permeated the membrane because of their low molecular weight distribution properties. The content of autochthonous protein-like (Ex/Em≈280 nm/334 nm of peak B and Ex/Em≈225 nm/328 nm of peak D) component was too low to be measured by high-sensitivity fluorescence spectrophotometer in the original water of Lake Hongfeng, Guizhou province. But they can be concentrated attribute to their high molecular weight distribution properties. The 3DEEM fluorescence spectroscopy of retentate exhibited evident protein-like fluorophores. Moreover, there had obviously difference in molecular weight between different sources of fulvic acid-like and protein-like components. It has been shown that the molecular weight distribution of autochthonous protein-like matter in Hongfeng lake is larger than allochthonous protein-like matter in Aha lake, Guizhou province. One was retained by membrane and another was permeated. Therefore, these techniques together will offer direct and convenient qualitative information about DOM in lake waters. |
