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首页> 外文期刊>Fuel >Effect of several salts on the elution behaviour of heavy hydrocarbon liquids during size exclusion chromatography with 1-methyl-2-pyrrolidinone as eluent
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Effect of several salts on the elution behaviour of heavy hydrocarbon liquids during size exclusion chromatography with 1-methyl-2-pyrrolidinone as eluent

机译：以1-甲基-2-吡咯烷酮为洗脱剂的体积排阻色谱法中几种盐对重烃液体洗脱行为的影响

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The addition of salts has been reported to shift chromatograms of coal-derived liquids to longer elution times (i.e. smaller molecular masses). The observation has been attributed to the disagglomeration of sample molecules. The aim of this work is to investigate whether size exclusion chromatograms (SEC) obtained, using NMP (1-methyl-2-pyrrolidinone) as eluent, are free from sample agglomeration. The direct addition of salts to the eluent does not allow distinguishing between (a) the effect of these salts on the large mass material and (b) distortions to the size exclusion mechanism introduced by the effect of the salt itself. The present work, attempts to resolve the two effects. Lithium bromide and trichloroacetic acid were added to solvents before use during the planar chromatographic (PC) fractionation of the samples. Any presumed disaggregation of the sample molecules would be expected to have taken place during this fractionation. The fractions thus separated from three coal-derived samples were examined by SEC. The apparently large molecular mass material observed in SEC does not disaggregate following PC elution in salty solvents. Indeed, the action of salty solvents was to displace from the silica of the PC-plates even larger mass materials than the solvent alone. The action of salts is to increase the polarity of the solvent and enhance its ability to displace larger and more polar molecules from the silica on the PC-plates. However, when the salts are added directly to the SEC eluent, they promote surface interactions between sample and packing. The observations thus obtained appear to reflect the distortion of the size exclusion mechanism rather than show disaggregation.
机译：据报道，加入盐会使煤衍生液体的色谱图移动到更长的洗脱时间（即较小的分子量）。该观察结果归因于样品分子的团聚。这项工作的目的是研究使用NMP（1-甲基-2-吡咯烷酮）作为洗脱液获得的尺寸排阻色谱图（SEC）是否没有样品团聚。将盐直接添加到洗脱液中无法区分（a）这些盐对大块物质的作用，以及（b）由盐本身的作用引起的尺寸排阻机理的扭曲。当前的工作试图解决这两种影响。在样品平面色谱（PC）分馏过程中使用之前，将溴化锂和三氯乙酸添加到溶剂中。预计在此分级分离过程中会发生样品分子的任何分解。通过SEC检查了从三个煤衍生样品中分离出的馏分。在咸溶剂中进行PC洗脱后，SEC中观察到的分子量较大的物质不会分解。的确，含盐溶剂的作用是从PC板的二氧化硅中移出比单独使用的溶剂更大质量的材料。盐的作用是增加溶剂的极性，并增强其从PC板上的二氧化硅上置换更大极性的分子的能力。但是，当将盐直接添加到SEC洗脱液中时，它们会促进样品和填料之间的表面相互作用。这样获得的观察结果似乎反映了尺寸排阻机制的扭曲，而不是显示出分类。

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