1
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Adrover A, Venditti C, Desmet G. On the modelling of the effective longitudinal diffusion in bi-continuous chromatographic beds. J Chromatogr A 2024; 1721:464817. [PMID: 38518515 DOI: 10.1016/j.chroma.2024.464817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/10/2024] [Accepted: 03/12/2024] [Indexed: 03/24/2024]
Abstract
We report on the possibility to extend to bi-continuous packings the two models for the effective longitudinal diffusion Deff, or B-term band broadening, recently proposed for discontinuous chromatographic beds. In bi-continuous packings, like monolithic columns, solutes experience a connected end-to-end pathway in both the mobile and stationary zones, as opposed to discontinuous packings, wherein the stationary adsorptive zone is distributed over a set of isolated elements. Since it is unclear whether a densely packed bed of spherical particles should be treated as a continuous or a bi-continuous medium, this extension is also crucial to fully understand the behaviour of packed particle beds. The proposed models for the effective longitudinal diffusion Deff originate from the adoption of the Two Zone Moment Analysis (TZMA) method by which Deff can be expressed as a linear combination of two essential quantities γm and γs, referred to as effective zone-diffusion factors. In the present work we propose two analytical models for γm and γs that now cover both the discontinuous and the bi-continuous case. To validate the theory, several bi-continuous packings are investigated, including the tetrahedral skeleton model (TSM), six different Triple Periodic Minimal Surface (TPMS) monoliths and randomly packed beds of spheres. For all of these, the models provide highly accurate results for Deff over a wide range of porosities and zone retention factors k″. The comparison with literature experimental data for both monolithic silica columns and columns packed with fully porous and porous-shell particles is also presented.
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Affiliation(s)
- Alessandra Adrover
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy.
| | - Claudia Venditti
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
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2
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Vankeerberghen B, Op de Beeck J, Desmet G. Column-Only Band Broadening in a Porous Shell Radially Elongated Pillar Array Column. Anal Chem 2024; 96:3618-3626. [PMID: 38350649 DOI: 10.1021/acs.analchem.3c05756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
In the quest for better performing separation media for liquid chromatography, micropillar array columns have received great interest over the past years. While previous research was mainly focused around micropillar array columns (μPACs) filled with cylindrical pillars, this contribution discusses μPACs with rectangular pillars, which, for the first time, have been anodized and hence carry a mesoporous shell. We report on a series of on-chip measurements of the band broadening and flow permeability in a μPAC with very wide radially elongated pillars (3·75 μm) and with an interpillar distance (2 μm) between that of the first (2.5 μm) and second generation (1.25 μm) of cylindrical μPACs. Because of the extreme flow path tortuosity, this type of μPAC can produce very large plate numbers over a short distance. Despite the relatively large interpillar distance, we obtain Hmin = 0.26 μm for a nearly unretained component (phase retention factor, k' ≈ 0.24) and Hmin = 0.79 μm for a retained component with k' ≈ 3. The kinetic performance in terms of separation impedance (Ei = 19) is considerably improved compared to cylindrical pillar μPACs (Ei in range 40-50) and is in excellent agreement with the theoretical value for an open tubular channel with a rectangular cross-section (Ei = 18). This shows that rectangular μPACs can be represented as a parallel bundle of interconnected open-tubular channels.
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Affiliation(s)
- Bert Vankeerberghen
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Jeff Op de Beeck
- Thermo Fisher Scientific, Technologiepark-Zwijnaarde 82, 9052 Gent, Belgium
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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3
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Adrover A, Venditti C, Desmet G. An alternative general model for the effective longitudinal diffusion in chromatographic beds filled with ordered porous particles. J Chromatogr A 2024; 1715:464598. [PMID: 38171067 DOI: 10.1016/j.chroma.2023.464598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 12/13/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024]
Abstract
The two-zone moment-analysis method for the determination of the dispersion tensor in hierarchical retentive porous media has been adopted to compute and model the effective longitudinal diffusion Deff, or equivalently the B-term band broadening, in chromatographic beds filled with ordered porous particles. On the one hand, this approach offers accurate numerical results for Deff while keeping computational expenses low. On the other hand, it also gives direct insight for the analytical modelling, readily revealings the two main essential quantities (resp. referred to as the mobile-zone and stationary-zone effective diffusion factors γm and γs) that contribute to Deff. Modelling these two main parameters provided us with two new analytical models for Deff: a general one, valid for diluted and concentrated packings and accurate in the whole range of relevant intra-particle diffusion coefficient Dpz, and an approximate one, reliable for diluted packings and accurate also for concentrated packings with low to intermediate values of Dpz. The large advantage of both models is that they do not need any fitting parameter because all the required information is incorporated into the experimentally accessible geometric obstruction factor in the mobile phase originating from the tortuosity of the through-pore space (limiting case of fully solid particles without any retention). These models hence serve as an alternative to the Effective Medium Theory (EMT) models used so far in the literature. To validate the theory, five ordered geometries have been investigated. The accuracy of the general model proposed has been quantified and found to be comparable with that of the 3rd order approximate Torquato model for four geometries, even for macro-porosities close to the close-packing limit. The case of a 2-d triangular array of ellipsoidal particles with different elongations is also investigated to show the general validity and applicability of the models.
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Affiliation(s)
- Alessandra Adrover
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy.
| | - Claudia Venditti
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
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4
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Redón L, Subirats X, Chapel S, Januarius T, Broeckhoven K, Rosés M, Cabooter D, Desmet G. Comprehensive analysis of the effective and intra-particle diffusion of weakly retained compounds in silica hydrophilic interaction liquid chromatography columns. J Chromatogr A 2024; 1713:464529. [PMID: 38029660 DOI: 10.1016/j.chroma.2023.464529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023]
Abstract
A detailed analysis of intra-particle volumes and layer thicknesses and their effect on the diffusion of solutes in hydrophilic interaction liquid chromatography (HILIC) was made. Pycnometric measurements and the retention volume of deuterated mobile phase constituents (water and acetonitrile) were used to estimate the void volume inside the column, including not only the volume of the mobile phase but also part of the enriched water solvent acting as the stationary phase in HILIC. The mobile phase (hold-up) volume accessible to non-retained components was estimated using a homologous series approach. The joint analysis of the different approaches indicated the formation of enriched water layers on the hydrophobic silica mesopore walls with a thickness varying significantly with mobile phase composition. The maximal thickness of the enriched water layers, which corresponded to the minimum void volume accessible to unretained solutes, marked a transition in the retention behavior of the studied analytes. Discrepancies between deuterated solvent measurements and pycnometry were explained by the existence of an irreplaceable water layer adsorbed on the silica surface. Regarding the diffusion behavior in HILIC, peak parking experiments were used to interpret the influence of the acetonitrile content on the effective diffusion coefficient Deff. A systematic decrease in Deff and molecular diffusion Dm was observed with decreasing acetonitrile concentration, primarily attributed to variations in mobile phase viscosity. Notably, Deff/Dm remained nearly unaffected by variations in mobile phase composition. Finally, the effective medium theory was used to make a comprehensive analysis of Dpart/Dm to study the contribution to band broadening when the solute resides in the mesopores. The obtained data unveiled a curvature with a minimum corresponding to conditions of maximum water-layer thickness and retention. For the weakly retained compounds (k' < 0.5) the Dpart/Dm-values were found to be relatively high (order of 0.35-0.5), which directly reflects the high γsDs/Dm-values that were observed (order 0.35-7).
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Affiliation(s)
- Lídia Redón
- Institute of Biomedicine (IBUB) and Department of Chemical Engineering and Analytical Chemistry, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Xavier Subirats
- Institute of Biomedicine (IBUB) and Department of Chemical Engineering and Analytical Chemistry, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Soraya Chapel
- Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
| | - Timothy Januarius
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
| | - Ken Broeckhoven
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
| | - Martí Rosés
- Institute of Biomedicine (IBUB) and Department of Chemical Engineering and Analytical Chemistry, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Deirdre Cabooter
- Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium.
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
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5
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Felletti S, Spedicato M, Bozza D, De Luca C, Presini F, Giovannini PP, Carraro M, Macis M, Cavazzini A, Catani M, Ricci A, Cabri W. Dimethyl carbonate as a green alternative to acetonitrile in reversed-phase liquid chromatography. Part I: Separation of small molecules. J Chromatogr A 2023; 1712:464477. [PMID: 37944433 DOI: 10.1016/j.chroma.2023.464477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 11/12/2023]
Abstract
Nowadays, environmental problems are drawing the attention of governments and international organisations, which are therefore encouraging the transition to green industrial processes and approaches. In this context, chemists can help indicate a suitable direction. Beside the efforts focused on greening synthetic approaches, currently also analytical techniques and separations are under observation, especially those employing large volumes of organic solvents, such as reversed-phase liquid chromatography (RPLC). Acetonitrile has always been considered the best performing organic modifier for RPLC applications, due to its chemical features (complete miscibility in water, UV transparency, low viscosity etc); nevertheless, it suffers of severe shortcomings, and most importantly, it does not fully comply with Environmental, Health and Safety (EHS) requirements. For these reasons, alternative greener solvents are being investigated, especially easily available alcohols. In this work, chromatographic performance of the most common solvents used in reversed-phase chromatography, i.e., acetonitrile, ethanol and isopropanol, have been compared to a scarcely used solvent, dimethyl carbonate (DMC). The analytes of interest were two small molecules, caffeine and paracetamol, whose kinetics and retention behaviour obtained with the four solvents have been compared, and all contributions to band broadening have been assessed. Results about kinetic performance are very promising, indicating that a small amount (7 % v/v) of DMC is able to produce the same efficiency as a 2.5-times larger ACN volume (18 % v/v), and larger efficiency than alcohols. This paper reports, for the first time, fundamental studies concerning the mass transfer phenomena when DMC is used as an organic solvent in RPLC, and, together with the companion paper, represents the results of a research whose final aim was to discover whether DMC is suitable for chromatographic applications both in linear and preparative conditions.
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Affiliation(s)
- Simona Felletti
- Department of Environmental and Prevention Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Matteo Spedicato
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Desiree Bozza
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Chiara De Luca
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Francesco Presini
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Pier Paolo Giovannini
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Marco Carraro
- Fresenius Kabi iPSUM, via San Leonardo 23, Villadose, Rovigo 45010, Italy
| | - Marco Macis
- Fresenius Kabi iPSUM, via San Leonardo 23, Villadose, Rovigo 45010, Italy
| | - Alberto Cavazzini
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy; Council for Agricultural Research and Economics, via della Navicella 2/4, Rome 00184, Italy
| | - Martina Catani
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy.
| | - Antonio Ricci
- Fresenius Kabi iPSUM, via San Leonardo 23, Villadose, Rovigo 45010, Italy.
| | - Walter Cabri
- Fresenius Kabi iPSUM, via San Leonardo 23, Villadose, Rovigo 45010, Italy; Department of Chemistry "Giacomo Ciamician", Alma Mater Studiorum - University of Bologna, Via F. Selmi 2, Bologna, Italy
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6
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Huygens B, Venditti C, Adrover A, Desmet G. Nonadditivity and Nonlinearity of Mobile and Stationary Zone Mass Transfer Resistances in Chromatography. Anal Chem 2023; 95:15199-15207. [PMID: 37791982 DOI: 10.1021/acs.analchem.3c01971] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Using a two-zone moment analysis (TZMA) method based on Brenner's generalized dispersion theory for two-dimensional (2D) and three-dimensional (3D) periodic media, we investigated the mechanisms for dispersion in particulate media for liquid chromatography. This was done using a set of plate height data covering an unprecedented wide range of retention factors, diffusion coefficients, and velocities, all computed with unequaled accuracy. Applying Giddings' additivity test, based on alternatingly making the diffusion coefficient in the mobile and stationary zones infinitely large, the dispersion data clearly indicate a lack of additivity. Although this lack could be directly understood by identifying the existence of multiple parallel mass transfer paths, the additivity assumption interestingly overestimates the true C term band broadening (typically by more than 10%, depending on conditions and dimensionality of the system). However, Giddings originally asserted the occurrence of parallel paths would always lead to an underestimation of the dispersion. The origin of the lack of additivity is analyzed in detail and qualitatively explained. Finally, we also established a generic framework for the modeling of the effect of the reduced velocity and the retention coefficient on the C term in ordered chromatographic media. This led to the introduction of a new expression for the mobile zone mass transfer term, which, unlike the currently used literature expression, contains the complete k″ dependency.
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Affiliation(s)
- Bram Huygens
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Claudia Venditti
- Department of Chemical Engineering, Materials, Environment, Sapienza Università di Roma, Via Eudossiana 18, 00184 Rome, Italy
| | - Alessandra Adrover
- Department of Chemical Engineering, Materials, Environment, Sapienza Università di Roma, Via Eudossiana 18, 00184 Rome, Italy
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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7
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Vankeerberghen B, Op de Beeck J, Desmet G. On-Chip Comparison of the Performance of First- and Second-Generation Micropillar Array Columns. Anal Chem 2023; 95:13822-13828. [PMID: 37677150 DOI: 10.1021/acs.analchem.3c01829] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Because of its dimensions, the recently introduced micropillar array columns are most suited for high-efficiency liquid chromatography separations in proteomics. Unlike the packed bed columns and capillary-based column formats, the micropillar array concept still has significant room to progress in terms of the reduction of its characteristic size (i.e., pillar diameter and interpillar distance) to open the road to even higher-efficiency separations and their applications. We report here on the on-chip comparison between first-generation (Gen 1) and second-generation (Gen 2) micropillar array columns wherein the pillar and interpillar size have been halved. Because of the on-chip measurements, the observed plate heights H represent the fundamental band broadening, devoid of any extra-column band-broadening effects. The observed reduction of H with a factor of 2 around the uopt-velocity and with a factor of 4 in the C-term dominated regime of the van Deemter-curve is in full agreement with the theoretically expected gain. This shows the pillar and interpillar size reduction could be effectuated without affecting the theoretical separation potential of the micropillar arrays. Compared to Gen 1, Gen 2 offers a 4-fold reduction of the required analysis time around the optimal velocity and about a 16-fold reduction in the C-term-dominated range.
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Affiliation(s)
- Bert Vankeerberghen
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Jeff Op de Beeck
- Thermo Fisher Scientific, Technologiepark-Zwijnaarde 82, 9052 Gent, Belgium
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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8
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Gritti F. Resolution limits of size exclusion chromatography columns identified from flow reversal and overcome by recycling liquid chromatography to improve the characterization of manufactured monoclonal antibodies. J Chromatogr A 2023; 1705:464219. [PMID: 37499525 DOI: 10.1016/j.chroma.2023.464219] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/06/2023] [Accepted: 07/15/2023] [Indexed: 07/29/2023]
Abstract
The flow reversal (FR) technique consists of reversing the flow direction along a chromatographic column. It is used to reveal the origin (such as poor column packing, active sites, or slow absorption/escape kinetics) for the resolution limit of 4.6 mm × 150 mm long columns packed with 1.7 μm 200 Å Bridge-Ethylene-Hybrid (BEHTM) Particles. These columns are used to separate manufactured monoclonal antibodies (mAb, ∼ 150 kDa) from their close impurities (or IdeS fragments, ∼ 100 kDa) by size exclusion chromatography (SEC). FR unambiguously demonstrates that the resolution limit of these SEC columns is primarily due to long-range flow velocity biases covering distances of at least 500 μm across the column diameter. This confirms the existence of center-to-wall flow heterogeneities which cause undesirable tailing for the mAb peak. Because the transverse dispersion coefficient (Dt=1.1 × 10-6 cm2/s) of mAbs across the column diameter is intrinsically low, the bandspreading of the mAb in a single flow direction is in part reversible upon reversing the flow direction. For the very same residence time in the column, the column efficiency is found to increase by +85% relative to that observed under conventional elution mode. The observed peak tailing of the mAb and its sub-units is not caused by active surface sites or by slow absorption/escape from the BEH Particles. Therefore, the most critical mAb impurities (hydrolytic degradation Fab/c and IdeS [Formula: see text] fragments) can only be successfully separated and quantified with acceptable accuracy by adopting alternate pumping recycling liquid chromatography (APRLC). APRLC enables the full baseline separation of the mAb and 100 kDa mAb fragments and partial separation of Fab/c and [Formula: see text] fragments after increasing the number of cycles to ten. It was made possible to accurately measure the relative abundances of the mAb (99.0 ± 0.1%), [Formula: see text] fragment (0.88 ± 0.03%), and Fab/c immunogenic fragment (0.13 ± 0.02%) in less than 45 min for a total mAb sample load of only 5 μg. Still, further improvements are needed to increase the sensitivity of the APRLC method and to reduce the solvent consumption by adopting narrow-bore 2.1 mm i.d. SEC columns.
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Affiliation(s)
- Fabrice Gritti
- Waters Corporation, Instrument/Core Research/Fundamental, Milford, MA, 01757, USA.
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9
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Felletti S, De Luca C, Mazzoccanti G, Gasparrini F, Manetto S, Franchina FA, Chenet T, Pasti L, Cavazzini A, Catani M. Understanding the Transition from High-Selective to High-Efficient Chiral Separations by Changing the Organic Modifier with Zwitterionic-Teicoplanin Chiral Stationary Phase. Anal Chem 2023. [PMID: 37294639 DOI: 10.1021/acs.analchem.3c01344] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The retention behavior of small molecules and N-protected amino acids on a zwitterionic teicoplanin chiral stationary phase (CSP), prepared on superficially porous particles (SPPs) of 2.0 μm particle diameter, has shown that efficiency and enantioselectivity, and so enantioresolution, dramatically change depending on the employed organic modifier. In particular, it was found that while methanol permits the boost of enantioselectivity and resolution of the amino acids, at the cost of efficiency, acetonitrile allows for the ability to reach extraordinary efficiency even at high flow rates (with reduced plate height <2 and up to 300,000 plates/m at the optimum flow rate). To understand these features, an approach based on the investigation of mass transfer through the CSP, the estimation of the binding constants of amino acids on the CSP, and the assessment of compositional properties of the interfacial region between bulk mobile phase and solid surface has been adopted.
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Affiliation(s)
- Simona Felletti
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Chiara De Luca
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Giulia Mazzoccanti
- Department of Drug Chemistry and Technology, "Sapienza" University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy
| | - Francesco Gasparrini
- Department of Drug Chemistry and Technology, "Sapienza" University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy
| | - Simone Manetto
- Department of Drug Chemistry and Technology, "Sapienza" University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy
| | - Flavio Antonio Franchina
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Tatiana Chenet
- Department of Environmental and Prevention Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Luisa Pasti
- Department of Environmental and Prevention Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Alberto Cavazzini
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Martina Catani
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
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10
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Tortuosity of hierarchical porous materials: Diffusion experiments and random walk simulations. Chem Eng Sci 2022. [DOI: 10.1016/j.ces.2022.118136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Li H, Desmet G, Jiang Z, Cabooter D. On the occurrence of very low intra-particle diffusion rates in zwitterionic hydrophilic interaction liquid chromatography polymer columns. J Chromatogr A 2022; 1683:463531. [DOI: 10.1016/j.chroma.2022.463531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 10/31/2022]
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12
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Januarius T, Desmet G, Broeckhoven K. Measurement of the molecular diffusion coefficient and the effective longitudinal diffusion under supercritical fluid chromatography conditions in packed bed columns. J Chromatogr A 2022; 1682:463485. [PMID: 36182682 DOI: 10.1016/j.chroma.2022.463485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 10/14/2022]
Abstract
The improvement of supercritical fluid chromatography (SFC) instrumentation enhanced its reliability and utility over the past decade. The further development of high speed and high resolution separations is however obstructed by the lack of accurate models for axial dispersion in SFC. This work is a first step to tackle this by developing more reliable methods to measure molecular (Dmol) and longitudinal diffusion (Deff) in SFC, as these affect all aspects of separation efficiency. In the present contribution, we report on an improved method, to enable more flexible, reliable and accurate measurements of Dmol in SFC using commercial instrumentation. A two-column variant of the stopped-flow experiment is proposed as an adapted set-up for measuring the effective longitudinal diffusion coefficient Deff in SFC-conditions. Using the set-ups for a number of test-compounds, it has been found that Deff, and the coefficients describing its constituent sub-processes (cf. particle diffusion Dpart and surface diffusion γsDs), all vary in a linearly proportional way with the bulk diffusion coefficient Dmol within a high degree of accuracy. It has also been found that Deff decreases much more sharply with increasing retention factor compared to LC. By applying the effective medium theory, it was found that the relative surface diffusion coefficient γsDs/Dmol decreases strongly with retention factor for the investigated solutes and column, in contrary to what is typically observed in reversed phase liquid chromatography. Results indicate that this might be related to a change in retention behavior of the analytes. Obviously, more analytes and conditions need to be explored to complete this picture and the extend range of applicability of these observations.
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Affiliation(s)
| | - Gert Desmet
- Vrije Universiteit Brussel, Pleinlaan 2, Brussel 1050, Belgium
| | - Ken Broeckhoven
- Vrije Universiteit Brussel, Pleinlaan 2, Brussel 1050, Belgium.
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13
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Broeckhoven K, Desmet G. Theory of separation performance and peak width in gradient elution liquid chromatography: A tutorial. Anal Chim Acta 2022; 1218:339962. [PMID: 35701036 DOI: 10.1016/j.aca.2022.339962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 04/06/2022] [Accepted: 05/18/2022] [Indexed: 11/26/2022]
Abstract
Separation performance in chromatography has been extensively studied since the dawn of the technique. Although the basic principles of band broadening and the resulting separation performance in isocratic elution are in general well known and understood, this is much less the case for gradient separations. In this tutorial, first the basic principles, concepts and parameters that determine separation performance, peak width and variance and analysis time in isocratic separations are reviewed. This is subsequently used to discuss the parameters that affect peak width in gradient elution, together with the concepts of plate count and plate height in this elution mode. In addition, the effect of peak compression in gradient elution is elaborated. Finally, the effect of extra-column dispersion on separation performance in gradient elution is discussed, and an overview of how these contributions can be experimentally evaluated is given.
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Affiliation(s)
- Ken Broeckhoven
- Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussel, Belgium.
| | - Gert Desmet
- Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussel, Belgium
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14
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Review of recent insights in the measurement and modelling of the B-term dispersion and related mass transfer properties in liquid chromatography. Anal Chim Acta 2022; 1214:339955. [DOI: 10.1016/j.aca.2022.339955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/11/2022] [Accepted: 05/14/2022] [Indexed: 11/23/2022]
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15
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Wernert V, Nguyen KL, Levitz P, Coasne B, Denoyel R. Impact of surface diffusion on transport through porous materials. J Chromatogr A 2022; 1665:462823. [DOI: 10.1016/j.chroma.2022.462823] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/03/2022] [Accepted: 01/10/2022] [Indexed: 11/24/2022]
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16
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Hara T, Baron GV, Hata K, Izumi Y, Bamba T, Desmet G. Performance of functionalized monolithic silica capillary columns with different mesopore sizes using radical polymerization of octadecyl methacrylate. J Chromatogr A 2021; 1651:462282. [PMID: 34144397 DOI: 10.1016/j.chroma.2021.462282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 11/29/2022]
Abstract
We report on the possibility to enhance the phase ratio and retention factor in silica monoliths. According to pioneering work done by Núñez et al. [1], this enhancement is pursued by applying a stationary phase layer via radical polymerization with octadecyl methacrylate (ODM) as an alternative to the customary octadecylsilylation (C18-derivatization). The difference in band broadening, retention factor and separation selectivity between both approaches was compared. Different hydrothermal treatment temperatures for the column preparation were applied to produce monolithic silica structures with three different mesopore sizes (resp. 10, 13, and 16 nm, as determined by argon physisorption) while maintaining similar domain size (sum of through-pore and skeleton size). It has been found that the columns with the poly(octadecyl methacrylate)-phase (ODM columns) provided a 60 to 80% higher retention factor in methanol-water mixture compared to the octadecylsilylated (ODS) columns produced by starting from similar silica backbone structures. In acetonitrile-water mixture, the enhancement is smaller (15 to 30% times higher), yet significant. By adjusting the fabrication conditions (for both the preparation of the monolithic backbones and the surface functionalization), the achieved retention factors (up k = 4.89 for pentylbenzene in 80:20% (v/v) methanol/water) are obviously higher than obtained in the pioneering study on ODM monoliths of Núñez et al. [1], and column clogging could be completely avoided. In addition, also separation efficiencies were significantly higher than shown in Ref. [1], with plate heights as low as 5.8 μm. These plate heights are however inferior to those observed on the ODS-modified sister columns. The difference can be explained by the slower intra-skeleton diffusion displayed by the ODM-modified columns, in turn caused by the larger obstruction to diffusion originating from the thicker stationary phase layer.
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Affiliation(s)
- Takeshi Hara
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; GL Sciences Inc., 237-2 Sayamagahara, Iruma, Saitama 358-0032, Japan
| | - Gino V Baron
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, Brussels B-1050, Belgium
| | - Kosuke Hata
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yoshihiro Izumi
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takeshi Bamba
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, Brussels B-1050, Belgium.
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17
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Nguyen KL, Wernert V, Denoyel R. Effect of the polydispersity on the dispersion of polymers through silicas having different morphologies (fully porous and core-shell particles and monoliths). J Chromatogr A 2021; 1641:461985. [PMID: 33611113 DOI: 10.1016/j.chroma.2021.461985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 11/26/2022]
Abstract
The effect of the polydispersity of polystyrenes on the dispersion through silicas having different morphologies (fully porous, core-shell particles and monoliths) was investigated. The heights equivalent to a theoretical plate (HETP) of those columns were measured for a small molecule (toluene) and a series of polystyrenes of different sizes in non-adsorbing conditions. The different contributions to the total HETP including polydispersity were determined experimentally. The longitudinal diffusion and the mass transfer resistance term were obtained from peak parking experiments. The eddy dispersion was obtained from models and experiments. The effect of polydispersity on the HETP values (Hpoly) can thus be calculated from the total HETP by substraction of the other contributions. The results were compared to the Knox model which surestimates the Hpoly values for porous and core-shell particles which is usually explained by an overestimation of the polydispersity index (PDI) given by the manufacturer. The PDI of two polymers (P02, Mw= 690 g.mol-1 and P03, Mw=1380 g.mol-1) was verified by liquid chromatography by separating each fraction of the polymer on the silica columns by using adsorbing conditions which are obtained with a mixture of heptane and THF. The PDI obtained are comparable to the PDI given by the manufacturer meaning that the assumptions made by Knox are not entirely valid. A direct method is proposed in this paper in order to determine Hpoly. In this method the excess of spreading as compared with a polymer with only one size corresponding to the average size is studied assuming the polymer size distribution is gaussian. The Hpoly values obtained by the direct method are comparable to the experimental values.
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Affiliation(s)
- Khac-Long Nguyen
- Aix-Marseille Université, CNRS, MADIREL, UMR 7246, Centre Saint-Jérôme, F-13397 Marseille cedex 20, France; Hanoi University of Mining and Geology, 18 Vien Street, Bac Tu Liem, Hanoi, Vietnam
| | - Véronique Wernert
- Aix-Marseille Université, CNRS, MADIREL, UMR 7246, Centre Saint-Jérôme, F-13397 Marseille cedex 20, France.
| | - Renaud Denoyel
- Aix-Marseille Université, CNRS, MADIREL, UMR 7246, Centre Saint-Jérôme, F-13397 Marseille cedex 20, France
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18
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Cabooter D, Song H, Makey D, Sadriaj D, Dittmann M, Stoll D, Desmet G. Measurement and modelling of the intra-particle diffusion and b-term in reversed-phase liquid chromatography. J Chromatogr A 2020; 1637:461852. [PMID: 33412290 DOI: 10.1016/j.chroma.2020.461852] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022]
Abstract
In an ongoing effort to better understand the underlying mechanisms of band broadening in particle-packed reversed-phase liquid chromatography columns, new models for intra-particle diffusion, representing an adsorption- and partition-type retention behavior, are proposed. These models assume the mesoporous zone inside the particles is subdivided in four distinct regions: a fraction f1 filled with bulk mobile phase, a fraction f2 enriched in pure organic modifier extending outside the stationary phase layer, a fraction f3 comprising the liquid surrounding the alkyl chains and a fraction f4 consisting of the stationary phase alkyl chains. Intra-particle diffusion is calculated as a residence time weighted average of the diffusion in these different regions. Experimental procedures and models are proposed to determine the volumes of these four regions and applied to three reversed-phase liquid chromatography columns with different pore sizes (80 Å versus 300 Å) and different stationary phase types (C18 versus C8). The newly proposed models are then applied to predict the intra-particle diffusion of butyrophenone across a wide range of retention factors (1 ≤ k" ≤ 40) in each of these columns. These predictions are compared to experimental data that are extracted from the effective diffusion coefficients of butyrophenone obtained via peak parking experiments. It is demonstrated that both adsorption- and partition-type models for intra-particle diffusion model the actual behavior of the test compound well, and require the determination of only one (partition) or two (adsorption) fitting factors: the obstruction to free movement the analytes experience from the alkyl chains in the retained state (partition and adsorption) and in the unretained state (adsorption). Finally, it is demonstrated that the major contributor to the intra-particle diffusion of retained compounds (k" > 2) is the diffusion these analytes undergo when retained in the organic-modifier enriched zone surrounding the alkyl chains (partition model) or when adsorbed onto the alkyl chains (adsorption model), confirming that surface diffusion plays an important role in the mass transfer of retained compounds in reversed-phase liquid chromatography columns.
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Affiliation(s)
- Deirdre Cabooter
- University of Leuven (KU Leuven), Department for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, Herestraat 49, Leuven, Belgium.
| | - Huiying Song
- University of Leuven (KU Leuven), Department for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, Herestraat 49, Leuven, Belgium
| | - Devin Makey
- Gustavus Adolphus College, Department of Chemistry, 800 West College Avenue, Saint Peter, USA
| | - Donatela Sadriaj
- University of Leuven (KU Leuven), Department for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, Herestraat 49, Leuven, Belgium
| | - Monika Dittmann
- Agilent Technologies R&D, Hewlett-Packard-Strasse 8, Waldbronn, Germany
| | - Dwight Stoll
- Gustavus Adolphus College, Department of Chemistry, 800 West College Avenue, Saint Peter, USA
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussel, Belgium
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19
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Felletti S, Catani M, Mazzoccanti G, De Luca C, Lievore G, Buratti A, Pasti L, Gasparrini F, Cavazzini A. Mass transfer kinetics on modern Whelk-O1 chiral stationary phases made on fully- and superficially-porous particles. J Chromatogr A 2020; 1637:461854. [PMID: 33387912 DOI: 10.1016/j.chroma.2020.461854] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 11/26/2022]
Abstract
In this work, a detailed study of mass transfer properties of trans-stilbene oxide (TSO) enantiomers on two Whelk-O1 chiral stationary phases (CSPs) has been performed. The CSPs were prepared by using both fully-porous silica particles of 2.5 μm particle diameter and superficially-porous ones of 2.6 μm particle diameter as base materials. By combining stop-flow and dynamic measurements in normal-phase conditions, the different contributions to mass transfer have been estimated. The study of intraparticle diffusion has revealed that the adsorption of both enantiomers is localized (i.e., characterized by absence of surface diffusion). The determination of thermodynamic binding constants (measured through adsorption isotherms) supports this finding.
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Affiliation(s)
- Simona Felletti
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Martina Catani
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Giulia Mazzoccanti
- Dept. of Drug Chemistry and Technology, Sapienza Universita di Roma, P.le A. Moro 5, 00185 Roma, Italy
| | - Chiara De Luca
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Giulio Lievore
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Alessandro Buratti
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Luisa Pasti
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Francesco Gasparrini
- Dept. of Drug Chemistry and Technology, Sapienza Universita di Roma, P.le A. Moro 5, 00185 Roma, Italy.
| | - Alberto Cavazzini
- Dept. of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy.
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20
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Matheuse F, Deridder S, Desmet G. An explicit expression for the retention factor and velocity dependency of the mobile zone mass transfer band broadening in packed spheres beds used in liquid chromatography. J Chromatogr A 2020; 1634:461710. [PMID: 33221656 DOI: 10.1016/j.chroma.2020.461710] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 10/23/2022]
Abstract
The present study proposes a ready-to-use analytical expression to calculate the mobile zone mass transfer contribution (hCm) in packed bed columns. For this purpose, first high-accuracy computations of the band broadening in a perfectly ordered sphere array (fcc-arrangement, external porosity ε=0.40) were made using computational fluid dynamics (CFD), covering a broad range of zone retention factors (2≤k''≤18) and reduced velocities (0≤νi≤48). Subsequently, these data were used to determine the value of the geometrical constants in a number of possible analytical expressions for the hCm-contribution. This fitting exercise showed the traditional literature approach, using the Wilson-Geankoplis correlation to calculate the dimensionless Sherwood (Sh) number for the mass transfer, leads to fitting errors on the hCm-term as large as 150%. Instead, a new correlation for Sh is established. In addition, we also explored the difference in fitting accuracy between hCm-expressions based on either a plug-flow or a laminar flow profile assumption. Surprisingly, no significant difference in fitting accuracy between both assumptions was observed. Finally, a best-fit analytical expression is proposed that can represent the CFD-computed band broadening data with an average absolute fitting error of Δh=0.005, corresponding to a relative error of 2.5% on the hCm-term and of only 0.3% on the total plate height in a perfectly ordered sphere packing. Defining the presently investigated fcc-ordered sphere array with external porosity=40% as the reference geometry for a perfect sphere packing, the established expression can be used as a new yardstick expression against which the degree of eddy-dispersion can be measured.
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Affiliation(s)
- Frederick Matheuse
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Sander Deridder
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium; Department of Chemical Engineering, Process and Environmental Technology Lab (PETLab), KU Leuven, Sint-Katelijne-Waver, Belgium
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.
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21
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Felletti S, De Luca C, Lievore G, Chenet T, Chankvetadze B, Farkas T, Cavazzini A, Catani M. Shedding light on mechanisms leading to convex-upward van Deemter curves on a cellulose tris(4-chloro-3-methylphenylcarbamate)-based chiral stationary phase. J Chromatogr A 2020; 1630:461532. [PMID: 32950816 DOI: 10.1016/j.chroma.2020.461532] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 11/16/2022]
Abstract
An unusual convex-upward van Deemter curve was observed for the more retained enantiomer of a chiral sulfoxide (2-(benzylsulfinyl)benzamide) on a cellulose tris(4-chloro-3-methylphenylcarbamate)-based chiral stationary phase (CSP), prepared on silica particles of 1000 Å pore size. In contrast, the firstly eluted enantiomer of the same molecule exhibited the traditional convex-downward van Deemter curve. A detailed kinetic and thermodynamic investigation has revealed that this unusual phenomenon, which however has already been observed in chiral chromatography, originates when the adsorption of the compound is very strong and the solid-phase diffusion negligible. Experimentally, the intraparticle diffusion of the more retained enantiomer of the sulfoxide was found to be one order of magnitude smaller than that of the first eluted one. Overall, this translates into very little longitudinal diffusion (b-term of van Deemter curve) accompanied by high solid-liquid mass transfer resistance (c-term). Finally the comparison with another, differently-substituted chiral sulfoxide (whose enantiomers both exhibit traditional van Deemter curve behavior) has allowed to correlate these findings to the specific characteristics of the molecule.
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Affiliation(s)
- Simona Felletti
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Chiara De Luca
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Giulio Lievore
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Tatiana Chenet
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, 0179 Tbilisi, Georgia
| | - Tivadar Farkas
- Phenomenex Inc., 411 Madrid Ave., Torrance, CA 90501, United States
| | - Alberto Cavazzini
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy.
| | - Martina Catani
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy.
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22
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Song H, Desmet G, Cabooter D. A Methodology for the Estimation and Modelling of the Obstruction Factor in the Expression for Mesopore Diffusion in Reversed-Phase Liquid Chromatography Particles. J Chromatogr A 2020; 1625:461285. [DOI: 10.1016/j.chroma.2020.461285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/27/2020] [Accepted: 05/28/2020] [Indexed: 01/19/2023]
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23
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Experimental investigation of the retention factor dependency of eddy dispersion in packed bed columns and relation to knox's empirical model parameters. J Chromatogr A 2020; 1626:461339. [DOI: 10.1016/j.chroma.2020.461339] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 11/18/2022]
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24
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Felletti S, De Luca C, Lievore G, Pasti L, Chenet T, Mazzoccanti G, Gasparrini F, Cavazzini A, Catani M. Investigation of mass transfer properties and kinetic performance of high‐efficiency columns packed with C
18
sub‐2 μm fully and superficially porous particles. J Sep Sci 2020; 43:1737-1745. [DOI: 10.1002/jssc.202000041] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Simona Felletti
- Department of Chemistry and Pharmaceutical SciencesUniversity of Ferrara Ferrara Italy
| | - Chiara De Luca
- Department of Chemistry and Pharmaceutical SciencesUniversity of Ferrara Ferrara Italy
| | - Giulio Lievore
- Department of Chemistry and Pharmaceutical SciencesUniversity of Ferrara Ferrara Italy
| | - Luisa Pasti
- Department of Chemistry and Pharmaceutical SciencesUniversity of Ferrara Ferrara Italy
| | - Tatiana Chenet
- Department of Chemistry and Pharmaceutical SciencesUniversity of Ferrara Ferrara Italy
| | - Giulia Mazzoccanti
- Department of Drug Chemistry and Technology“Sapienza” University of Rome Rome Italy
| | - Francesco Gasparrini
- Department of Drug Chemistry and Technology“Sapienza” University of Rome Rome Italy
| | - Alberto Cavazzini
- Department of Chemistry and Pharmaceutical SciencesUniversity of Ferrara Ferrara Italy
| | - Martina Catani
- Department of Chemistry and Pharmaceutical SciencesUniversity of Ferrara Ferrara Italy
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25
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Galluzzo MD, Loo WS, Wang AA, Walton A, Maslyn JA, Balsara NP. Measurement of Three Transport Coefficients and the Thermodynamic Factor in Block Copolymer Electrolytes with Different Morphologies. J Phys Chem B 2020; 124:921-935. [DOI: 10.1021/acs.jpcb.9b11066] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Michael D. Galluzzo
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Whitney S. Loo
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
| | - Andrew A. Wang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
| | - Amber Walton
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
| | - Jacqueline A. Maslyn
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Nitash P. Balsara
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Joint Center for Energy Storage Research (JCESR), Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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26
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Geibel C, Dittrich K, Woiwode U, Kohout M, Zhang T, Lindner W, Lämmerhofer M. Evaluation of superficially porous particle based zwitterionic chiral ion exchangers against fully porous particle benchmarks for enantioselective ultra-high performance liquid chromatography. J Chromatogr A 2019; 1603:130-140. [DOI: 10.1016/j.chroma.2019.06.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 06/10/2019] [Accepted: 06/10/2019] [Indexed: 12/20/2022]
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27
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Vanderlinden K, Desmet G, Bell DS, Broeckhoven K. Detailed efficiency analysis of columns with a different packing quality and confirmation via total pore blocking. J Chromatogr A 2018; 1581-1582:55-62. [PMID: 30446265 DOI: 10.1016/j.chroma.2018.10.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 10/26/2018] [Accepted: 10/29/2018] [Indexed: 11/16/2022]
Abstract
We report on a systematic study involving columns with a clearly different efficiency (4 distinct quality groups) obtained by packing the columns that were C18 bonded and endcapped with a different carbon loading. Using B-term analysis (via peak parking) and theoretical models to estimate the magnitude of the Cm- and Cs-term contributions, it could be concluded that the difference in efficiency among the groups was entirely due to a difference in eddy dispersion. As such, the columns provided an ideal testing ground to verify how well the total pore blocking (TPB)-method can be used to probe differences in packing heterogeneity. In agreement with earlier literature observations, it turns out the TPB-method is much more sensitive to packing heterogeneities than the eddy dispersion (Heddy)-contribution measured under open-pore conditions via B- and C- term subtraction. Typically, differences in Heddy on the order of 0.1-0.5μm translate into a difference on the order of 0.5-2μm in the TPB mode. This confirms the TPB as a powerful technique to make very sensitive measurements of the homogeneity of packed beds.
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Affiliation(s)
- Kim Vanderlinden
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussels, Belgium
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussels, Belgium
| | - David S Bell
- MilliporeSigma/Supelco, 595 North Harrison Road, Bellefonte, PA 16823, USA
| | - Ken Broeckhoven
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussels, Belgium.
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28
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Hara T, Izumi Y, Nakao M, Hata K, Baron GV, Bamba T, Desmet G. Silica-based hybrid porous layers to enhance the retention and efficiency of open tubular capillary columns with a 5 μm inner diameter. J Chromatogr A 2018; 1580:63-71. [DOI: 10.1016/j.chroma.2018.10.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/09/2018] [Accepted: 10/14/2018] [Indexed: 12/16/2022]
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29
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Numerical and analytical investigation of the possibilities to enhance the thermal conductivity of core-shell particle packed beds. J Chromatogr A 2018; 1575:26-33. [DOI: 10.1016/j.chroma.2018.08.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/23/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022]
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30
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Schmitt K, Woiwode U, Kohout M, Zhang T, Lindner W, Lämmerhofer M. Comparison of small size fully porous particles and superficially porous particles of chiral anion-exchange type stationary phases in ultra-high performance liquid chromatography: effect of particle and pore size on chromatographic efficiency and kinetic performance. J Chromatogr A 2018; 1569:149-159. [DOI: 10.1016/j.chroma.2018.07.056] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/13/2018] [Accepted: 07/18/2018] [Indexed: 11/28/2022]
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31
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Lambert N, Felinger A. The effect of the frictional heat on retention and efficiency in thermostated or insulated chromatographic columns packed with sub-2-μm particles. J Chromatogr A 2018; 1565:89-95. [DOI: 10.1016/j.chroma.2018.06.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/11/2018] [Accepted: 06/16/2018] [Indexed: 11/28/2022]
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32
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Lunn DB, Yun YJ, Jorgenson JW. Retention and effective diffusion of model metabolites on porous graphitic carbon. J Chromatogr A 2017; 1530:112-119. [PMID: 29157608 PMCID: PMC5711574 DOI: 10.1016/j.chroma.2017.11.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 11/12/2022]
Abstract
The study of metabolites in biological samples is of high interest for a wide range of biological and pharmaceutical applications. Reversed phase liquid chromatography is a common technique used for the separation of metabolites, but it provides little retention for polar metabolites. An alternative to C18 bonded phases, porous graphitic carbon has the ability to provide significant retention for both non-polar and polar analytes. The goal of this work is to study the retention and effective diffusion properties of porous graphitic carbon, to see if it is suitable for the wide injection bands and long run times associated with long, packed capillary-scale separations. The retention of a set of standard metabolites was studied for both stationary phases over a wide range of mobile phase conditions. This data showed that porous graphitic carbon benefits from significantly increased retention (often >100 fold) under initial gradient conditions for these metabolites, suggesting much improved ability to focus a wide injection band at the column inlet. The effective diffusion properties of these columns were studied using peak-parking experiments with the standard metabolites under a wide range of retention conditions. Under the high retention conditions, which can be associated with retention after injection loading for gradient separations, Deff/Dm∼0.1 for both the C18-bonded and porous graphitic carbon columns. As C18 bonded particles are widely, and successfully utilized for long gradient separations without issue of increasing peak width from longitudinal diffusion, this suggests that porous graphitic carbon should be amenable for long runtime gradient separations as well.
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Affiliation(s)
- Daniel B Lunn
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Young J Yun
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - James W Jorgenson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Wang Q, Yang C, Wang H, Qiu T. Optimization of process-specific catalytic packing in catalytic distillation process: A multi-scale strategy. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2017.09.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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34
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Futagami S, Hara T, Ottevaere H, Baron GV, Desmet G, De Malsche W. Preparation and evaluation of mesoporous silica layers on radially elongated pillars. J Chromatogr A 2017; 1523:234-241. [DOI: 10.1016/j.chroma.2017.06.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 11/29/2022]
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35
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Song H, Desmet G, Cabooter D. Assessment of intra-particle diffusion in hydrophilic interaction liquid chromatography and reversed-phase liquid chromatography under conditions of identical packing structure. J Chromatogr A 2017; 1523:204-214. [DOI: 10.1016/j.chroma.2017.06.068] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 10/19/2022]
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36
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Catani M, Ismail OH, Gasparrini F, Antonelli M, Pasti L, Marchetti N, Felletti S, Cavazzini A. Recent advancements and future directions of superficially porous chiral stationary phases for ultrafast high-performance enantioseparations. Analyst 2017; 142:555-566. [DOI: 10.1039/c6an02530g] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This review focuses on the use of superficially porous particles (SPPs) as chiral stationary phases for ultra-high performance liquid enantioseparations.
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Affiliation(s)
- Martina Catani
- Dept. of Chemistry and Pharmaceutical Sciences
- University of Ferrara
- 44121 Ferrara
- Italy
| | - Omar H. Ismail
- Department of Drug Chemistry and Technology
- “Sapienza” Università di Roma
- 00185 Roma
- Italy
| | - Francesco Gasparrini
- Department of Drug Chemistry and Technology
- “Sapienza” Università di Roma
- 00185 Roma
- Italy
| | - Michela Antonelli
- Department of Drug Chemistry and Technology
- “Sapienza” Università di Roma
- 00185 Roma
- Italy
| | - Luisa Pasti
- Dept. of Chemistry and Pharmaceutical Sciences
- University of Ferrara
- 44121 Ferrara
- Italy
| | - Nicola Marchetti
- Dept. of Chemistry and Pharmaceutical Sciences
- University of Ferrara
- 44121 Ferrara
- Italy
| | - Simona Felletti
- Dept. of Chemistry and Pharmaceutical Sciences
- University of Ferrara
- 44121 Ferrara
- Italy
| | - Alberto Cavazzini
- Dept. of Chemistry and Pharmaceutical Sciences
- University of Ferrara
- 44121 Ferrara
- Italy
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37
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Characterization of the Kinetic Performance of Silica Monolithic Columns for Reversed-Phase Chromatography Separations. ADVANCES IN CHROMATOGRAPHY 2016. [DOI: 10.1201/9781315370385-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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38
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Vanderheyden Y, Broeckhoven K, Desmet G. Peak deconvolution to correctly assess the band broadening of chromatographic columns. J Chromatogr A 2016; 1465:126-42. [DOI: 10.1016/j.chroma.2016.08.058] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 01/24/2023]
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39
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Deridder S, Catani M, Cavazzini A, Desmet G. A theoretical study on the advantage of core-shell particles with radially-oriented mesopores. J Chromatogr A 2016; 1456:137-44. [DOI: 10.1016/j.chroma.2016.05.062] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 05/17/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022]
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40
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Catani M, Ismail OH, Cavazzini A, Ciogli A, Villani C, Pasti L, Bergantin C, Cabooter D, Desmet G, Gasparrini F, Bell DS. Rationale behind the optimum efficiency of columns packed with new 1.9μm fully porous particles of narrow particle size distribution. J Chromatogr A 2016; 1454:78-85. [DOI: 10.1016/j.chroma.2016.05.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 05/07/2016] [Accepted: 05/10/2016] [Indexed: 12/12/2022]
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41
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Wei TC, Mack A, Chen W, Liu J, Dittmann M, Wang X, Barber WE. Synthesis, characterization, and evaluation of a superficially porous particle with unique, elongated pore channels normal to the surface. J Chromatogr A 2016; 1440:55-65. [DOI: 10.1016/j.chroma.2016.02.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/14/2016] [Accepted: 02/04/2016] [Indexed: 10/22/2022]
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42
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Callewaert M, Desmet G, Ottevaere H, De Malsche W. Detailed kinetic performance analysis of micromachined radially elongated pillar array columns for liquid chromatography. J Chromatogr A 2016; 1433:75-84. [DOI: 10.1016/j.chroma.2015.12.086] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/17/2015] [Accepted: 12/18/2015] [Indexed: 11/28/2022]
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43
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Song H, Desmet G, Cabooter D. Evaluation of the Kinetic Performance Differences between Hydrophilic-Interaction Liquid Chromatography and Reversed-Phase Liquid Chromatography under Conditions of Identical Packing Structure. Anal Chem 2015; 87:12331-9. [DOI: 10.1021/acs.analchem.5b03697] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Huiying Song
- Department
for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, KU Leuven, Herestraat 49, Leuven, Belgium
| | - Gert Desmet
- Department
of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium
| | - Deirdre Cabooter
- Department
for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, KU Leuven, Herestraat 49, Leuven, Belgium
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44
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Andrés A, Broeckhoven K, Desmet G. Methods for the experimental characterization and analysis of the efficiency and speed of chromatographic columns: A step-by-step tutorial. Anal Chim Acta 2015; 894:20-34. [DOI: 10.1016/j.aca.2015.08.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/08/2015] [Accepted: 08/13/2015] [Indexed: 11/26/2022]
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45
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Desmet G, Cabooter D, Broeckhoven K. Graphical Data Representation Methods To Assess the Quality of LC Columns. Anal Chem 2015; 87:8593-602. [DOI: 10.1021/ac504473p] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussels, Belgium
| | - Deirdre Cabooter
- KU Leuven−University of Leuven, Department for Pharmaceutical
and Pharmacological Sciences, Pharmaceutical Analysis, B-3000 Leuven, Belgium
| | - Ken Broeckhoven
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussels, Belgium
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46
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Heaton JC, McCalley DV. Comparison of the kinetic performance and retentivity of sub-2μm core–shell, hybrid and conventional bare silica phases in hydrophilic interaction chromatography. J Chromatogr A 2014; 1371:106-16. [DOI: 10.1016/j.chroma.2014.10.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 09/01/2014] [Accepted: 10/07/2014] [Indexed: 10/24/2022]
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47
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Deridder S, Vanmessen A, Nakanishi K, Desmet G, Cabooter D. Experimental and numerical validation of the effective medium theory for the B-term band broadening in 1st and 2nd generation monolithic silica columns. J Chromatogr A 2014; 1351:46-55. [DOI: 10.1016/j.chroma.2014.04.099] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 04/07/2014] [Accepted: 04/30/2014] [Indexed: 10/25/2022]
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48
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De Bruyne S, De Malsche W, Deridder S, Gardeniers H, Desmet G. In Situ Measurement of the Transversal Dispersion in Ordered and Disordered Two-Dimensional Pillar Beds for Liquid Chromatography. Anal Chem 2014; 86:2947-54. [DOI: 10.1021/ac403147q] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Selm De Bruyne
- Department
of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
- MESA+ Research
Institute, University of Twente, Enschede, The Netherlands
| | - Wim De Malsche
- Department
of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
- MESA+ Research
Institute, University of Twente, Enschede, The Netherlands
| | - Sander Deridder
- Department
of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Han Gardeniers
- MESA+ Research
Institute, University of Twente, Enschede, The Netherlands
| | - Gert Desmet
- Department
of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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49
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Wernert V, Bouchet R, Denoyel R. Impact of the solute exclusion on the bed longitudinal diffusion coefficient and particle intra-tortuosity determined by ISEC. J Chromatogr A 2014; 1325:179-85. [DOI: 10.1016/j.chroma.2013.12.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 12/05/2013] [Accepted: 12/06/2013] [Indexed: 10/25/2022]
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50
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Desmet G. A finite parallel zone model to interpret and extend Giddings’ coupling theory for the eddy-dispersion in porous chromatographic media. J Chromatogr A 2013; 1314:124-37. [DOI: 10.1016/j.chroma.2013.09.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 11/16/2022]
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