Morphology and Separation Efficiency of Low-Aspect-Ratio Capillary Ultrahigh Pressure Liquid Chromatography Columns
Morphology and Separation Efficiency of Low-Aspect-Ratio Capillary Ultrahigh Pressure Liquid Chromatography Columns
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DOI：
10.1021/ac300326k
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发表时间：
2012-05-15
影响因子：
7.4
通讯作者：
Tallarek, Ulrich
中科院分区：
文献类型：
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作者：
Bruns, Stefan;Grinias, James P.;Tallarek, Ulrich
我们推导出床形态和色谱分离效率之间的定量关系的毛细管柱填充与子2 μ m的颗粒，覆盖毛细管内径从10到75 μ m。我们的研究重点是壁效应及其对谱带展宽的影响，在增加柱-颗粒直径（纵横）比。我们接近这些复杂的影响，由共聚焦激光扫描显微镜成像的几千个粒子组成的重建列段的形态分析。径向颗粒间孔隙度剖面，包括壁效应量化通过一个整体的孔隙度偏差，标量测量，证明是一个一般的描述transcolumn孔隙度的异质性。它与相关的transcolumn涡流色散，其中占主导地位的带加宽的毛细管和可视化的板高度曲线由一个简单的速度成比例的条款。我们的综合方法确定了导致效率降低的包装结构特征，如，在不同纵横比下壁效应的细微变化中，或在较大直径柱中由于壁-床界面附近填充空隙的数量增加而导致的粒度偏析效应。
We derive a quantitative relationship between the bed morphology and the chromatographic separation efficiency of capillary columns packed with sub-2 mu m particles, covering capillary inner diameters from 10 to 75 mu m. Our study focuses on wall effects and their impact on band broadening at increasing column-to-particle diameter (aspect) ratios. We approach these complex effects by a morphological analysis of reconstructed column segments composed of several thousand particles that were imaged by confocal laser scanning microscopy. Radial interparticle porosity profiles including wall effects are quantified through an integral porosity deviation, a scalar measure that proves to be a general descriptor of transcolumn porosity heterogeneity. It correlates with the associated transcolumn eddy dispersion, which dominates band broadening in the capillaries and is visualized in the plate height curves by a simple velocity-proportional term. Our comprehensive approach identifies the packing structure features that contribute to decreased efficiency as reflected, e.g., in subtle variations of the wall effect at different aspect ratios, or a particle size-segregation effect in larger-diameter columns as a result of an increased number of packing voids near the wall-bed interface.