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首页> 外文期刊>Aquatic Sciences >Characterizing the properties of dissolved organic matter isolated by XAD and C-18 solid phase extraction and ultrafiltration
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Characterizing the properties of dissolved organic matter isolated by XAD and C-18 solid phase extraction and ultrafiltration

机译：表征通过XAD和C-18固相萃取和超滤分离的溶解有机物的性质

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The properties of aquatic dissolved organic matter (DOM) isolated by solid phase extraction (SPE) C-18 cartridges, ultrafiltration, and XAD chromatography are compared. Samples taken from the Suwannee River, Georgia, USA and McDonalds Branch in the Pine Barrens, New Jersey, USA were chosen to represent waters where DOM originates from predominantly terrestrially-derived (allochthonous) precursors. Pony Lake, Antarctica represented an exclusively algal/microbially-derived ( autochthonous) DOM. Fluorescence, UV absorption, C-13 NMR spectroscopy, and high-pressure size exclusion chromatography (HPSEC) were employed to discern differences and similarities between the DOM isolated by these three methods. Only subtle differences between isolation methods were observed for the terrestrially derived DOM samples when assayed by light and fluorescence spectroscopy. Conversely, the Pony Lake DOM isolates exhibit greater variability when analyzed by these methods. C-13-NMR analyses showed structural differences between the methods for all samples. HPSEC analysis also revealed differences with the C-18 isolates exhibiting the highest molecular weights. Thus, it appears that each method isolates sufficiently different fractions of DOM that can only be delineated when a consortium of analytical methods are used to assay the samples. Nonetheless real differences between autochthonous and allochthonous derived DOM were observed with the algal-derived samples exhibiting high fluorescence ratios and lower aromaticity relative to the terrestrially derived materials. These results demonstrate that caution must be exercised when interpreting DOM reactivity data that rely upon the use of specific fractions.
机译：比较了通过固相萃取（SPE）C-18柱，超滤和XAD色谱分离的水生溶解有机物（DOM）的性能。选择从美国佐治亚州苏万尼河和美国新泽西州派恩巴伦斯的麦当劳分公司采集的样品来代表DOM源自主要是陆生（杂水）前体的水域。南极州的小马湖（Pony Lake）代表了一个唯一的藻类/微生物来源（自生）DOM。使用荧光，紫外吸收，C-13 NMR光谱和高压尺寸排阻色谱法（HPSEC）来识别通过这三种方法分离出的DOM之间的差异和相似性。用光和荧光光谱法分析时，对于陆地来源的DOM样品，在分离方法之间仅观察到细微的差异。相反，当用这些方法分析时，Pony Lake DOM分离物表现出更大的变异性。 C-13-NMR分析显示所有样品的方法之间的结构差异。 HPSEC分析还揭示了与分子量最高的C-18分离株的差异。因此，似乎每种方法都分离出足够不同的DOM组分，只有当使用分析方法联盟对样品进行分析时才能描述。但是，在藻类衍生的样品中，相对于陆地衍生的材料显示出高的荧光比率和较低的芳香性，观察到了原生和异源DOM之间的实际差异。这些结果表明，在解释依赖于特定分数的DOM反应性数据时，必须谨慎行事。

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