Ellipsoidal particles for liquid chromatography: Fluid mechanics, efficiency and wall effects.
Ellipsoidal particles for liquid chromatography: Fluid mechanics, efficiency and wall effects.
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DOI：
10.1016/j.chroma.2018.09.051
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发表时间：
2018-12
期刊：
影响因子：
--
通讯作者：
M. Schure;R. Maier
中科院分区：
文献类型：
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作者：
M. Schure;R. Maier
用高分辨流体力学和布朗动力学模拟研究了椭球粒子作为高效液相色谱的填充介质。采用填充毛细管柱和周期性边界条件(PBC)床进行模拟，以研究在没有壁面影响的情况下的传输。椭球粒子的性能是在一系列长宽比上进行评估的。给出了用来比较球形和椭圆形颗粒性能指标的有效直径的定义，并讨论了比较球形和椭圆形颗粒填料所必需的标度关系式。用PBCS计算了分离阻抗，结果表明，椭圆形颗粒的分离阻抗与球形颗粒的分离阻抗基本相同。用平板高度衡量，椭圆形填料的效率低于球形颗粒填料，而压降高于球形填料，而椭圆形颗粒填料在填充圆柱形毛细管时，壁面效应较小。对于椭圆形填料，填料孔隙率和壁区内流动的径向变化较小。填充毛细管的最小折合塔板高度和分离阻抗清楚地表明了椭圆形颗粒与球形颗粒相比的优势。这种预测的性能优势还有待于在实际实践中得到验证。
Ellipsoidal particles are investigated as packing media for liquid chromatography using high resolution fluid mechanics and Brownian dynamics simulations. The simulations are conducted with packed capillary columns, as well as beds with periodic boundary conditions (PBCs) to study transport in the absence of wall effects. The performance of ellipsoidal particles is evaluated over a range of aspect ratios. The definition of effective diameter used to compare sphere and ellipsoidal particle performance metrics is presented and discussed along with scaling relationships which are necessary to compare sphere and ellipsoidal particle packs.Ellipsoidal particle packs are found to be inferior to sphere packs using PBCs to study chromatographic dispersion. The separation impedance was calculated with PBCs and shown to be approximately the same with ellipsoidal particles as those of spheres. Efficiency of ellipsoidal packs, as measured by plate height, is lower than spherical particle packs and the pressure drop is higher than sphere packs when using PBCs.However, a smaller wall effect is shown for ellipsoidal particles when packing cylindrical capillaries. Radial variations in packing porosity and in flow within the wall region are smaller for ellipsoidal packings. The minimum reduced plate height and the separation impedance for the packed capillaries clearly demonstrate the advantages of ellipsoidal particles compared to spherical particles. This predicted performance advantage remains to be demonstrated in actual practice.