Structural radial heterogeneity of a silica-based wide-bore monolithic column

Mriziq, Khaled S.; Abia, Jude A.; Lee, Young-Mi; Guiochon, Georges

doi:10.1016/j.chroma.2008.04.004

Cited by 53 publications

(25 citation statements)

References 23 publications

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“…Trans-column eddies were always suspected as be a source of band broadening in packed columns, as already observed in packed columns [15][16][17][18] and more recently in monolithic columns. [19][20][21] Still, this observation does not explain why the A-term is significantly higher when access to the mesopore volume is blocked. A new model of eddy dispersion is needed.…”

Section: Introductionmentioning

confidence: 52%

“…18,21,43,44 In good packed columns, the linear velocity is slightly higher in the center than at the column wall ($3-7%). In monolithic columns, the opposite is true.…”

Section: Transcolumn Eddy Dispersionmentioning

confidence: 97%

“…In monolithic columns, the opposite is true. 21 The migration linear velocity, u R (x), at the reduced radial position x is then:…”

Section: Transcolumn Eddy Dispersionmentioning

confidence: 99%

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Impact of retention on trans‐column velocity biases in packed columns

Gritti

Guiochon

2009

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).The heights equivalent to a theoretical plate of a weakly and strongly retained compounds were measured on two packed columns having different average mesopore sizes. The measurements were carried out in two different cases, with access to the mesopores by the sample molecules blocked (filled with n-nonane) or not. The experimental results demonstrate that the eddy dispersion terms of both columns are significantly smaller for porous than for nonporous particles. Two simultaneous phenomena explain this observation. First, packed columns are radially heterogeneous which causes significant trans-column velocity biases warping the bands. Second, radial dispersion contributes to mass transfer across the column, relaxing the radial concentration gradients that are caused by these velocity biases. The impact of these biases is minimized when the pores of the particles are not blocked; it decreases with increasing residence time and radial dispersion coefficient of the solutes. V

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Section: Introductionmentioning

confidence: 52%

“…18,21,43,44 In good packed columns, the linear velocity is slightly higher in the center than at the column wall ($3-7%). In monolithic columns, the opposite is true.…”

Section: Transcolumn Eddy Dispersionmentioning

confidence: 97%

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Impact of retention on trans‐column velocity biases in packed columns

Gritti

Guiochon

2009

AIChE Journal

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“…Guiochon et al found heterogeneity in the network structure from the center to the wall region on first generation Chromolith by placing a detection point at different radial positions 109 . Tallarek et al.…”

Section: Improvements Proposed Based On the Characterization Of Firstmentioning

confidence: 99%

Core–Shell, Ultrasmall Particles, Monoliths, and Other Support Materials in High-Performance Liquid Chromatography

Tanaka¹,

McCalley

2015

Anal. Chem.

150

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“…In order to achieve high column efficiency, it is essential that the mobile phase percolates through the bed following piston flow, so that the radial distribution of the mobile phase velocity is flat [36]. Guiochon demonstrated that a wide-bore silica monolithic column had a radially heterogeneous structure surrounding a nearly homogeneous core at the column center [109].…”

Section: Introductionmentioning

confidence: 99%

Polymethacrylate monolithic columns for capillary liquid chromatography

Urban

Jandera²

2008

J of Separation Science

121

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In recent years, continuous separation media have attracted considerable attention because of the advantages they offer over packed columns. This research resulted in two useful monolithic material types, the first based on modified silica gel and the second on organic polymers. This work attempts to review advances in the development, characterization, and applications of monolithic columns based on synthetic polymers in capillary chromatography, with the main focus on monolithic beds prepared from methacrylate-ester based monomers. The polymerization conditions used in the production of polymethacrylate monolithic capillary columns are surveyed, with attention being paid to the concentrations of monomers, porogen solvents, and polymerization initiators as the system variables used to control the porous and hydrodynamic properties of the monolithic media. The simplicity of their preparation as well as the possibilities of controlling of their porous properties and surface chemistries are the main benefits of the polymer monolithic capillary columns in comparison to capillary columns packed with particulate materials. The application areas considered in this review concern mainly separations in reversed-phase chromatography, ion-exchange chromatography, hydrophobic and hydrophilic interaction modes; enzyme immobilization and sample preparation in the capillary chromatography format are also addressed.

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Structural radial heterogeneity of a silica-based wide-bore monolithic column

Cited by 53 publications

References 23 publications

Impact of retention on trans‐column velocity biases in packed columns

Impact of retention on trans‐column velocity biases in packed columns

Core–Shell, Ultrasmall Particles, Monoliths, and Other Support Materials in High-Performance Liquid Chromatography

Polymethacrylate monolithic columns for capillary liquid chromatography

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