In Situ Measurement of the Transversal Dispersion in Ordered and Disordered Two-Dimensional Pillar Beds for Liquid Chromatography

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• 作者：Selm De Bruyne ; Wim De Malsche ; Sander Deridder ; Han Gardeniers ; Gert Desmet
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：March 18, 2014
• 年：2014
• 卷：86
• 期：6
• 页码：2947-2954
• 全文大小：388K
• 年卷期：v.86,no.6(March 18, 2014)
• ISSN：1520-6882

文摘

Using a fully transparent micropillar array chip and an optical 鈥渋njection鈥?setup capable of writing pulsed and continuous patterns into the flow by uncaging a fluorescent dye, highly detailed measurements of the transversal dispersion process in two-dimensional (2D) chromatographic beds could be made. With the use of water-glycerol mobile phase spanning a wide range of viscosities, the obtained data cover a broad range of reduced velocities (0 < 谓 < 3000) and show a clear leveling-off of the transversal dispersion coefficient at large reduced velocities. With dependence on the packing density, this leveling-off occurs at a value of about D_trans/D_mol = 10 (蔚 = 0.4), D_trans/D_mol = 4 (蔚 = 0.6) and D_trans/D_mol = 2.5 (蔚 = 0.8). Another interesting observation that could be made is that the effect of the bed order on the observed transversal dispersion process is relatively small. The observed leveling-off in the relation between the measured D_trans values and the reduced liquid velocity furthermore clearly invalidates the classical Galton-board model, predicting a linear increase of D_trans with the reduced velocity. On the other hand, it corroborates a recently proposed series-connection transport model for D_trans in 2D porous media.