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Yamada K, Miyagawa A, Honma R, Nagatomo S, Nakatani K. Effect of Organic Solvent on the Mass Transfer Mechanism of Coumarin 102 in a Single Octadecylsilyl Silica Gel/Organic Solvent-Water System by Laser Trapping and Fluorescence Microspectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:14303-14310. [PMID: 38958592 DOI: 10.1021/acs.langmuir.4c00878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Understanding mass transfer kinetics within individual porous particles is crucial for theoretically explaining the retention and elution behaviors in chromatography and drug delivery. Using laser trapping and fluorescence microspectroscopy, we investigated the diffusion mechanism of coumarin 102 (C102) into single octadecylsilyl particle in acetonitrile (ACN)/water, N,N-dimethylformamide (DMF)/water, and 1-butanol (BuOH)/water solutions. The intraparticle diffusion behavior of C102 was evaluated using the spherical diffusion equation, allowing us to determine the intraparticle diffusion coefficients (Dintra): (8-10) × 10-9 cm2 s-1 for ACN, (10-16) × 10-9 cm2 s-1 for DMF, and (4-6) × 10-9 cm2 s-1 for BuOH. The obtained Dintra values were further analyzed using a pore and surface diffusion model. Thus, we revealed that the diffusion mechanism of C102 differed depending on the organic solvent: surface diffusion for ACN and DMF and pore and surface diffusions for BuOH were observed. This difference is attributed to the formation of a concentrated liquid phase of ACN and DMF at the interface of the alkyl chain and the bulk solution in the pore.
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Affiliation(s)
- Kazuki Yamada
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Akihisa Miyagawa
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Ren Honma
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Shigenori Nagatomo
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Kiyoharu Nakatani
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
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2
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Niezen LE, Sasaki T, Sadriaj D, Ritchie H, Broeckhoven K, Cabooter D, Desmet G. Detailed analysis of the effective and intra-particle diffusion coefficient of proteins at elevated pressure in columns packed with wide-pore core-shell particles. J Chromatogr A 2024; 1713:464538. [PMID: 38043163 DOI: 10.1016/j.chroma.2023.464538] [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: 10/22/2023] [Revised: 11/23/2023] [Accepted: 11/26/2023] [Indexed: 12/05/2023]
Abstract
To determine the efficiency that can be obtained in a packed-bed liquid-chromatography column for a particular analyte, a correct determination of the molecular and effective diffusion coefficients (Dm and Deff) of the analyte is required. The latter is usually obtained via peak parking experiments wherein the flow is stopped. As a result, the column pressure rapidly dissipates and the measurement is essentially conducted at ambient pressure. This is problematic for analytes whose retention depends on pressure, such as proteins and potentially other large (dipolar) molecules. In that case, a conventional peak parking experiment is expected to lead to large errors in Deff. To obtain a better estimate ofDeff, the present study reports on the use of a set-up enabling peak parking measurements under pressurized conditions. This approach allowed us to report, for the first time, Deff for proteins at elevated pressure under retained conditions. First, Deff was determined at a (average) pressure of about 105 bar for a set of proteins with varying size, namely: bradykinin, insulin, lysozyme, β-lactoglobulin, and carbonic anhydrase in a column packed with 400 Å core-shell particles. The obtained data were then compared to those of several small analytes: acetophenone, propiophenone, benzophenone, valerophenone, and hexanophenone. A clear trend between Deff and analyte size was observed. The set-up was then used to determine Deff of bradykinin and lysozyme at variable (average) pressures ranging from 28 bar to 430 bar. These experiments showed a decrease in intra-particle and surface diffusion with pressure, which was larger for lysozyme than bradykinin. The data show that pressurized peak parking experiments are vital to correctly determine Deff when the analyte retention varies significantly with pressure.
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Affiliation(s)
- Leon E Niezen
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussel, Belgium
| | - Tsukasa Sasaki
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussel, Belgium
| | - Donatela Sadriaj
- University of Leuven (KU Leuven), Department for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, Herestraat 49, Leuven, Belgium
| | - Harald Ritchie
- Advanced Materials Technology, Silverside Rd, Wilmington, DE, USA
| | - Ken Broeckhoven
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussel, Belgium
| | - Deirdre Cabooter
- University of Leuven (KU Leuven), Department for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, Herestraat 49, Leuven, Belgium
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussel, Belgium.
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3
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Retention and mass transfer properties of the series of unbonded, amide-bonded, and alkylsulfobetaine-bonded ethylene bridged hybrid hydrophilic interaction liquid chromatography columns. J Chromatogr A 2023; 1692:463828. [PMID: 36804802 DOI: 10.1016/j.chroma.2023.463828] [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: 12/07/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 02/09/2023]
Abstract
This work investigates the link between the retentivity and the stationary phase to mobile phase mass transfer resistance of hydrophilic interaction liquid chromatography (HILIC) columns packed with the same base ethylene-bridged hybrid particles (BEH). The retention volumes, the plate heights, and the volume of the adsorbed water layer were measured for the ACQUITYTM UPLCTM BEHTM 130 Å HILIC Column (unbonded BEH), ACQUITY UPLC BEH 130 Å Amide Column (amide group attached), and AtlantisTM Premier BEH 95 Å Z-HILIC (zwitterionic group attached) Column. The method of Guo (toluene retention volumes in pure acetonitrile and in the HILIC eluent) was validated from the UNIFAC group-contribution method and applied to measure accurately the water layer volumes in these columns. A strong correlation was found between the retention volumes of most neutral polar analytes and the volume of the water layer adsorbed in the HILIC column. The fraction of the pore volume occupied by the water layer increases significantly from the BEH HILIC Column to the BEH Amide Column, and to the BEH Z-HILIC Column. This is explained by the water solvation of the attached ligands in the pore volume of the BEH Particles and to the smaller average mesopore size of the BEH Z-HILIC Particles. A second and strong correlation is also observed between the water content in the HILIC particle and the stationary phase to mobile phase mass transfer resistance of the HILIC columns at high mobile phase linear velocities. The measured intra-particle diffusivity normalized to the bulk diffusion coefficient decreased from 0.33 (BEH HILIC Column) to 0.10 (BEH Amide Column) and to only 0.03 (BEH Z-HILIC Column) for comparable retention of cytosine. These results are fully consistent with the higher viscosity of the internal eluent (higher water content) and higher internal obstruction for diffusion (smaller mesopores and internal porosity) in the BEH Z-HILIC Particles. Still, in gradient elution mode, the peak capacity was found to be 18% higher for the BEH Z-HILIC Column than that on the BEH Amide Column because the retention factors at elution were smaller when maintaining the same analysis time and starting eluent composition.
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4
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Lenčo J, Jadeja S, Naplekov DK, Krokhin OV, Khalikova MA, Chocholouš P, Urban J, Broeckhoven K, Nováková L, Švec F. Reversed-Phase Liquid Chromatography of Peptides for Bottom-Up Proteomics: A Tutorial. J Proteome Res 2022; 21:2846-2892. [PMID: 36355445 DOI: 10.1021/acs.jproteome.2c00407] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The performance of the current bottom-up liquid chromatography hyphenated with mass spectrometry (LC-MS) analyses has undoubtedly been fueled by spectacular progress in mass spectrometry. It is thus not surprising that the MS instrument attracts the most attention during LC-MS method development, whereas optimizing conditions for peptide separation using reversed-phase liquid chromatography (RPLC) remains somewhat in its shadow. Consequently, the wisdom of the fundaments of chromatography is slowly vanishing from some laboratories. However, the full potential of advanced MS instruments cannot be achieved without highly efficient RPLC. This is impossible to attain without understanding fundamental processes in the chromatographic system and the properties of peptides important for their chromatographic behavior. We wrote this tutorial intending to give practitioners an overview of critical aspects of peptide separation using RPLC to facilitate setting the LC parameters so that they can leverage the full capabilities of their MS instruments. After briefly introducing the gradient separation of peptides, we discuss their properties that affect the quality of LC-MS chromatograms the most. Next, we address the in-column and extra-column broadening. The last section is devoted to key parameters of LC-MS methods. We also extracted trends in practice from recent bottom-up proteomics studies and correlated them with the current knowledge on peptide RPLC separation.
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Affiliation(s)
- Juraj Lenčo
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Siddharth Jadeja
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Denis K Naplekov
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Oleg V Krokhin
- Department of Internal Medicine, Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, 799 JBRC, 715 McDermot Avenue, WinnipegR3E 3P4, Manitoba, Canada
| | - Maria A Khalikova
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Petr Chocholouš
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Jiří Urban
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00Brno, Czech Republic
| | - Ken Broeckhoven
- Department of Chemical Engineering (CHIS), Faculty of Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050Brussel, Belgium
| | - Lucie Nováková
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - František Švec
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
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5
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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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6
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Huygens B, Song H, Cabooter D, Desmet G. Detailed numerical analysis of the effect of radial column heterogeneities on peak parking experiments with slowly diffusing analytes. J Chromatogr A 2021; 1656:462557. [PMID: 34563893 DOI: 10.1016/j.chroma.2021.462557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/07/2021] [Accepted: 09/12/2021] [Indexed: 11/27/2022]
Abstract
The origin of the peak skewness that can be observed when applying the deconvolution method to isolate the diffusion process from the flow processes for peak parking experiments conducted under conditions of slow radial equilibration and strong trans-column velocity gradients was investigated. Numerical simulations were carried out for a variety of trans-column velocity profiles and a broad range of experimental conditions and system parameters were investigated. Results show that, under the aforementioned conditions, the traditionally employed variance subtraction method displays a consistent error which follows the dynamics of the diffusive relaxation during both the peak parking and the flow steps. It is also found that, under the same conditions, the peak deconvolution method is bound to produce deconvoluted "parking-only" peaks that are strongly asymmetric, despite the perfectly symmetric nature of the pure diffusion process marking this parking step. It is shown that this asymmetry is acquired during the flow step following the parking stop. During this step, parked and non-parked peaks are deformed in different ways, despite being subjected to the same trans-column velocity profile. This different deformation cannot be filtered away with the deconvolution or the variance subtraction method, hence introducing an error. Solutions to alleviate the peak skewness and the variance error consist of parking the peak close to the inlet or the outlet or exiting the parked peak through the column inlet (flow reversal method). Under the considered conditions, these approaches could reduce the error on the measured effective diffusion coefficient up to 87%. Carrying out the variance subtraction or the deconvolution process with a peak that has also been parked for a substantially long parking time instead of using a "no-parking" peak as is customary done, is another option to counter the effect.
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Affiliation(s)
- Bram Huygens
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussel, Belgium
| | - Huiying Song
- KU Leuven, Department for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, Herestraat 49, Leuven, Belgium
| | - Deirdre Cabooter
- KU Leuven, Department for Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, Herestraat 49, Leuven, Belgium
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, 1050 Brussel, Belgium.
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7
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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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8
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Gritti F, Hochstrasser J, Svidrytski A, Hlushkou D, Tallarek U. Morphology-transport relationships in liquid chromatography: Application to method development in size exclusion chromatography. J Chromatogr A 2020; 1620:460991. [DOI: 10.1016/j.chroma.2020.460991] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/13/2020] [Accepted: 02/20/2020] [Indexed: 12/14/2022]
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9
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Schultze-Jena A, Boon M, de Winter D, Bussmann P, Janssen A, van der Padt A. Predicting intraparticle diffusivity as function of stationary phase characteristics in preparative chromatography. J Chromatogr A 2020; 1613:460688. [DOI: 10.1016/j.chroma.2019.460688] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/04/2019] [Accepted: 11/06/2019] [Indexed: 10/25/2022]
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10
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Gritti F, Tanaka N. Slow injector-to-column sample transport to maximize resolution in liquid chromatography: Theory versus practice. J Chromatogr A 2019; 1600:219-237. [DOI: 10.1016/j.chroma.2019.04.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/15/2019] [Accepted: 04/22/2019] [Indexed: 01/08/2023]
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11
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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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12
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Characterization of radial and axial heterogeneities of chromatographic columns by flow reversal. J Chromatogr A 2018; 1567:164-176. [DOI: 10.1016/j.chroma.2018.07.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/05/2018] [Accepted: 07/02/2018] [Indexed: 11/20/2022]
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13
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Gritti F. A stochastic view on column efficiency. J Chromatogr A 2018; 1540:55-67. [DOI: 10.1016/j.chroma.2018.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/01/2018] [Accepted: 02/04/2018] [Indexed: 12/20/2022]
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14
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On the relationship between radial structure heterogeneities and efficiency of chromatographic columns. J Chromatogr A 2018; 1533:112-126. [DOI: 10.1016/j.chroma.2017.12.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/11/2017] [Accepted: 09/23/2017] [Indexed: 11/18/2022]
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15
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Methodologies to determine b-term coefficients revisited. J Chromatogr A 2018; 1532:124-135. [DOI: 10.1016/j.chroma.2017.11.070] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/16/2017] [Accepted: 11/30/2017] [Indexed: 11/19/2022]
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16
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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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17
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Gritti F. Impact of straight, unconnected, radially-oriented, and tapered mesopores on column efficiency: A theoretical investigation. J Chromatogr A 2017; 1485:70-81. [DOI: 10.1016/j.chroma.2017.01.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 01/09/2017] [Accepted: 01/11/2017] [Indexed: 11/25/2022]
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18
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Haas CP, Müllner T, Kohns R, Enke D, Tallarek U. High-performance monoliths in heterogeneous catalysis with single-phase liquid flow. REACT CHEM ENG 2017. [DOI: 10.1039/c7re00042a] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
On-line control and monitoring in heterogeneous catalysis utilizing high-performance supports allows rapid screening of intrinsic reaction parameters in continuous-flow mode.
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Affiliation(s)
- Christian P. Haas
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Tibor Müllner
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Richard Kohns
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
- Institute of Chemical Technology
| | - Dirk Enke
- Institute of Chemical Technology
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Ulrich Tallarek
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
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19
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Andrade-Eiroa A, Canle M, Leroy-Cancellieri V, Cerdà V. Solid-phase extraction of organic compounds: A critical review (Part I). Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2015.08.015] [Citation(s) in RCA: 265] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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20
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Gao H, Cong J. Effects of Intraparticle Mass Transfer Parameters on Separation Region of Simulated Moving Bed. J LIQ CHROMATOGR R T 2015. [DOI: 10.1080/10826076.2015.1048872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Hong Gao
- Department of Physics, Anshan Normal University, Anshan, Liaoning, P. R. China
| | - Jingxiang Cong
- Center of Separation Technologies, University of Science and Technology Liaoning, Anshan, Liaoning, P. R. China
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21
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Gritti F, Guiochon G. The quantitative impact of the mesopore size on the mass transfer mechanism of the new 1.9 μm fully porous Titan-C18 particles II – Analysis of biomolecules. J Chromatogr A 2015; 1392:10-9. [DOI: 10.1016/j.chroma.2015.02.075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/26/2015] [Accepted: 02/27/2015] [Indexed: 11/16/2022]
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22
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Gritti F, Guiochon G. The quantitative impact of the mesopore size on the mass transfer mechanism of the new 1.9 μm fully porous Titan-C18 particles. I: Analysis of small molecules. J Chromatogr A 2015; 1384:76-87. [DOI: 10.1016/j.chroma.2015.01.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/15/2015] [Accepted: 01/15/2015] [Indexed: 10/24/2022]
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23
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The relative importance of the adsorption and partitioning mechanisms in hydrophilic interaction liquid chromatography. J Chromatogr A 2015; 1376:112-25. [DOI: 10.1016/j.chroma.2014.11.087] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/28/2014] [Accepted: 11/29/2014] [Indexed: 11/18/2022]
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24
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Gritti F, Guiochon G. Separation of peptides and intact proteins by electrostatic repulsion reversed phase liquid chromatography. J Chromatogr A 2014; 1374:112-121. [PMID: 25488252 DOI: 10.1016/j.chroma.2014.11.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 11/30/2022]
Abstract
A new brand of BEH-C18 hybrid particles chemically bonded to a leash carrying an amine group permits the implementation of electrostatic repulsive interactions chromatography. Using columns packed with this material, the influence of the concentration of positive charges bonded to the BEH-C18 surface on the overloaded band profiles of a few positively charged peptides and proteins was investigated in the gradient elution mode. Three columns packed with endcapped BEH-C18 particles bonded with three different surface-charge densities (LOW, MEDIUM and HIGH) were used and compared with those provided by a column packed with non-doped, endcapped BEH-C18 particles. The surface concentrations of fixed charges in the LOW, MEDIUM and HIGH columns were estimated at 0.029, 0.050, and 0.064μmol/m(2), for example, about two orders of magnitude smaller than the surface density of bonded C18 chains (2.1μmol/m(2)). Three different mobile phase additives (0.1% v/v of trifluoro-acetic, phosphoric, and formic acid) were used to optimize the purification levels of proteins under different loading conditions. The weak ion-pairing ions (formate and phosphate) generate smaller retention but broader, more fronting band profiles than those eluted with a stronger ion-pairing ion (trifluoroactate). This effect is worse in the presence of fixed charges at the surface of the BEH-C18 particles. This was explained by an enhanced anti-Langmuirian adsorption behavior of the charged proteins in the presence of fixed surface charges. As the protein concentration increases in the bulk, so does the internal ionic strength, the electrostatic repulsive interactions weaken, and retention increases. Band fronting is mostly eliminated by replacing weak ion-pairing acids with TFA with which the adsorption isotherm remains weakly langmuirian. Faster but still complete gradient separation of insulin and myoglobin were achieved with the HIGH column than with the reference neutral column, despite a measurable loss in selectivity.
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Affiliation(s)
- Fabrice Gritti
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA.
| | - Georges Guiochon
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA.
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Mass transport of small retained molecules in polymer-based monolithic columns. J Chromatogr A 2014; 1362:49-61. [DOI: 10.1016/j.chroma.2014.07.065] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 11/21/2022]
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Gritti F, Bell DS, Guiochon G. Particle size distribution and column efficiency. An ongoing debate revived with 1.9μm Titan-C18 particles. J Chromatogr A 2014; 1355:179-92. [DOI: 10.1016/j.chroma.2014.06.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 06/06/2014] [Accepted: 06/10/2014] [Indexed: 10/25/2022]
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27
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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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28
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Gritti F, Guiochon G. The rationale for the optimum efficiency of columns packed with new 1.9μm fully porous Titan-C18 particles-a detailed investigation of the intra-particle diffusivity. J Chromatogr A 2014; 1355:164-78. [PMID: 24969087 DOI: 10.1016/j.chroma.2014.05.076] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 05/26/2014] [Accepted: 05/27/2014] [Indexed: 12/01/2022]
Abstract
In a previous report, it was reported that columns packed with fully porous 1.9μm Titan-C18 particles provided a minimum reduced plate height as small as 1.7 for the most retained compound (n-octanophenone) under RPLC conditions. These particles are characterized by a relatively narrow size distribution with a relative standard deviation (RSD) of only 10%. A column packed with classical 5μm Symmetry-C18 particles, used as a reference RPLC column, generated a minimum reduced plate height of 2.1 for the same retained compound. This work demonstrates that this was due to an unusually low intra-particle diffusivity across these particles, which leads to a small longitudinal diffusion coefficient along the column. The demonstration is based on the combination of accurate measurements of the height equivalent to a theoretical plate (HETP), inverse size exclusion chromatography (ISEC), peak parking (PP), and minor disturbance method (MDM) experiments. The experimental results show that the reduced eddy dispersion HETP term (A=0.8 for a reduced velocity of 5), the internal particle porosity (ϵp=0.35), and the enrichment of acetonitrile in the pore volume (75% acetonitrile in the bulk, 85% inside the mesoporous volume) are identical on both the Titan-C18 and Symmetry-C18 columns. The difference between the internal structures of these two brands of RPLC-C18 fully porous particles lies in the values of the internal obstruction factor γp, which is 0.42 for the Symmetry-C18 but only 0.26 for the Titan-C18 particles. This is in part related to the diffusion hindrance due to the small average pore size of the Titan-C18 particles, around 59Å versus 77Å for Symmetry-C18 particles. A simple model of constriction along diffusion paths having the shape of a truncated cone suggests that the width of the pore size distribution (RSD of 30% and 20% for Titan-C18 and Symmetry-C18 particles) is mostly responsible for the difference in their obstruction factors.
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Affiliation(s)
- Fabrice Gritti
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA
| | - Georges Guiochon
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA.
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Possible resolution gain in enantioseparations afforded by core–shell particle technology. J Chromatogr A 2014; 1348:87-96. [DOI: 10.1016/j.chroma.2014.04.041] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/08/2014] [Accepted: 04/14/2014] [Indexed: 11/21/2022]
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30
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Mass transfer mechanism in chiral reversed phase liquid chromatography. J Chromatogr A 2014; 1332:35-45. [DOI: 10.1016/j.chroma.2014.01.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/12/2014] [Accepted: 01/14/2014] [Indexed: 11/19/2022]
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31
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Evaluation of the kinetic performance of new prototype 2.1mm×100mm narrow-bore columns packed with 1.6μm superficially porous particles. J Chromatogr A 2014; 1334:30-43. [DOI: 10.1016/j.chroma.2014.01.065] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/17/2014] [Accepted: 01/20/2014] [Indexed: 11/21/2022]
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32
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Vasudevan V, Loh KC. Transcolumn dispersion in a computational mimic of an analytical silica monolith reconstructed from sub-microtomographic scans using computational fluid dynamics. Sep Purif Technol 2014. [DOI: 10.1016/j.seppur.2013.10.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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33
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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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34
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Gritti F, Guiochon G. Impact of the nature and composition of the mobile phase on the mass transfer mechanism in chiral reversed phase liquid chromatography. Application to the minimization of the solvent cost in chiral separations. J Chromatogr A 2014; 1327:57-65. [DOI: 10.1016/j.chroma.2013.12.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/03/2013] [Accepted: 12/04/2013] [Indexed: 10/25/2022]
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35
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The van Deemter equation: Assumptions, limits, and adjustment to modern high performance liquid chromatography. J Chromatogr A 2013; 1302:1-13. [DOI: 10.1016/j.chroma.2013.06.032] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/12/2013] [Accepted: 06/13/2013] [Indexed: 11/24/2022]
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36
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Gritti F, Guiochon G. Mass transfer mechanism in hydrophilic interaction chromatography. J Chromatogr A 2013; 1302:55-64. [DOI: 10.1016/j.chroma.2013.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/28/2013] [Accepted: 06/01/2013] [Indexed: 10/26/2022]
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Gritti F, Guiochon G. Comparison between the intra-particle diffusivity in the hydrophilic interaction chromatography and reversed phase liquid chromatography modes. Impact on the column efficiency. J Chromatogr A 2013; 1297:85-95. [DOI: 10.1016/j.chroma.2013.04.055] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 04/16/2013] [Accepted: 04/18/2013] [Indexed: 11/26/2022]
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38
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Gritti F, Guiochon G. Perspectives on the Evolution of the Column Efficiency in Liquid Chromatography. Anal Chem 2013; 85:3017-35. [DOI: 10.1021/ac3033307] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fabrice Gritti
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-1600, United States
| | - Georges Guiochon
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996-1600, United States
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Speed-resolution properties of columns packed with new 4.6 μm Kinetex-C18 core–shell particles. J Chromatogr A 2013; 1280:35-50. [DOI: 10.1016/j.chroma.2013.01.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 12/20/2012] [Accepted: 01/03/2013] [Indexed: 11/21/2022]
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40
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Repeatability of the efficiency of columns packed with sub-3μm core–shell particles: Part II. 2.7μm Halo-ES-Peptide-C18 particles in 4.6mm and 2.1mm×100mm column formats. J Chromatogr A 2012; 1252:45-55. [DOI: 10.1016/j.chroma.2012.05.063] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 05/15/2012] [Accepted: 05/16/2012] [Indexed: 11/22/2022]
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41
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Gritti F, Guiochon G. Repeatability of the efficiency of columns packed with sub-3μm core–shell particles: Part I. 2.6μm Kinetex-C18 particles in 4.6mm and 2.1mm×100mm column formats. J Chromatogr A 2012; 1252:31-44. [DOI: 10.1016/j.chroma.2012.05.072] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 05/17/2012] [Accepted: 05/21/2012] [Indexed: 10/28/2022]
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42
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The obstruction factor in size-exclusion chromatography. 2. The interparticle, intraparticle, and total obstruction factors. J Chromatogr A 2012; 1241:69-75. [PMID: 22560342 DOI: 10.1016/j.chroma.2012.04.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/05/2012] [Accepted: 04/08/2012] [Indexed: 11/22/2022]
Abstract
"Obstruction factor" is a generic rubric under which are usually gathered the interparticle, intraparticle, stationary phase, and total obstruction factors, γ(e), γ(p), γ(s), and γ(t), respectively. These, in turn, affect longitudinal diffusion and stationary, mobile phase, and stagnant mobile phase mass transfer. We conclude here our investigation into the various obstruction factors operative in size-exclusion chromatography (SEC). Stop-flow experiments were employed to determine either the interparticle (for analytes with K(SEC)=0) or the total (for analytes with K(SEC)>0) obstruction factor, and these results were combined with those from variable-flow-rate experiments which provided the intraparticle obstruction factor. Because of minimal enthalpic interactions between the analytes and stationary phase, in SEC γ(s)≈0, which allows for isolation of the other obstruction factors. A relationship between γ(t), γ(e), and γ(p) was proposed for SEC, based on previous independent work and dependent upon the various column porosities. This relationship was extended to hydrodynamic chromatography, a technique in which, ideally, both γ(s) and γ(p) are equal to zero.
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Gritti F, Guiochon G. Measurement of the eddy dispersion term in chromatographic columns. II. Application to new prototypes of 2.3 and 3.2mm I.D. monolithic silica columns. J Chromatogr A 2012; 1227:82-95. [DOI: 10.1016/j.chroma.2011.12.065] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/14/2011] [Accepted: 12/19/2011] [Indexed: 11/30/2022]
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Gritti F, Guiochon G. Measurement of the eddy dispersion term in chromatographic columns: III. Application to new prototypes of 4.6mm I.D. monolithic columns. J Chromatogr A 2012; 1225:79-90. [DOI: 10.1016/j.chroma.2011.12.055] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 12/14/2011] [Accepted: 12/15/2011] [Indexed: 12/01/2022]
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45
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Mass transfer kinetics, band broadening and column efficiency. J Chromatogr A 2012; 1221:2-40. [DOI: 10.1016/j.chroma.2011.04.058] [Citation(s) in RCA: 216] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/20/2011] [Accepted: 04/21/2011] [Indexed: 11/23/2022]
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46
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Guiochon G, Beaver LA. Separation science is the key to successful biopharmaceuticals. J Chromatogr A 2011; 1218:8836-58. [DOI: 10.1016/j.chroma.2011.09.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 09/04/2011] [Accepted: 09/05/2011] [Indexed: 10/17/2022]
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47
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Gritti F, Guiochon G. Experimental validation of physico-chemical models of effective diffusion in chromatographic columns packed with superficially porous particles. Chem Eng Sci 2011. [DOI: 10.1016/j.ces.2011.08.043] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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48
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Gritti F, Farkas T, Heng J, Guiochon G. On the relationship between band broadening and the particle-size distribution of the packing material in liquid chromatography: theory and practice. J Chromatogr A 2011; 1218:8209-21. [PMID: 21993511 DOI: 10.1016/j.chroma.2011.09.034] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 09/11/2011] [Accepted: 09/13/2011] [Indexed: 11/24/2022]
Abstract
The influence of the particle size distribution (PSD) on the band broadening and the efficiency of packed columns is investigated on both theoretical and practical viewpoints. Each of the classical contributions to mass transfer kinetics, those due to longitudinal diffusion, eddy dispersion, and solid-liquid mass transfer resistance are measured and analyzed in terms of their expected and observed intensity as a function of the PSD of mixtures of the commercially available packing materials, 5 and 3 μm Luna-C₁₈ particles (Phenomenex, Torrance, CA, USA). Six 4.6 mm × 150 mm columns were packed with different mixtures of these two materials. The efficiencies of these columns were measured for a non-retained and a retained analytes in a mixture of acetonitrile and water. The longitudinal diffusion coefficient was directly measured by the peak parking method. The solid-liquid mass transfer coefficient was measured from the combination of the peak parking method, the best model of effective diffusion coefficient and the actual PSDs of the different particle mixtures measured by Coulter counter experiments. The eddy diffusion term was measured according to a recently developed protocol, by numerical integration of the peak profiles. Our results clearly show that the PSD has no measurable impact on any of the coefficients of the van Deemter equation. On the contrary and surprisingly, adding a small fraction of large particles to a batch of small particles can improve the quality of the packing of the fine particles. Our results indirectly confirm that the success of sub-3 μm shell particles is due to the roughness of their external surface, which contributes to eliminate most of the nefarious wall effects.
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Affiliation(s)
- Fabrice Gritti
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA
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49
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Diffusion models in chromatographic columns packed with fully and superficially porous particles. Chem Eng Sci 2011. [DOI: 10.1016/j.ces.2011.04.039] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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50
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Gritti F, Guiochon G. Measurement of the eddy diffusion term in chromatographic columns. I. Application to the first generation of 4.6mm I.D. monolithic columns. J Chromatogr A 2011; 1218:5216-27. [DOI: 10.1016/j.chroma.2011.05.101] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/25/2011] [Accepted: 05/30/2011] [Indexed: 11/30/2022]
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