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Poeira RG, Siopa D, Anacleto P, Sadewasser S, Dale PJ. Optical Measurement of the Stoichiometry of Thin-Film Compounds Synthetized From Multilayers: Example of Cu(In,Ga)Se2. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1847-1855. [PMID: 37850643 DOI: 10.1093/micmic/ozad105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/26/2023] [Accepted: 09/18/2023] [Indexed: 10/19/2023]
Abstract
The properties of centimeter-sized thin-film compound semiconductors depend upon the morphology and chemical composition of the multiple submicrometer-thick elemental and alloy precursor layers from which they are synthesized. The challenge is to characterize the individual precursor layers over these length scales during a multistep synthesis without altering or contaminating them. Conventional electron and X-ray-based morphological and compositional techniques are invasive, require preparation, and are thus incompatible with in-line synthesis processes. In a proof-of-concept study, we applied confocal laser scanning microscopy (CLSM) as a noninvasive optical imaging technique, which measures three-dimensional surface profiles with nanoscale resolution, to this challenge. Using an array of microdots containing Cu(In,Ga)Se2 semiconductor layers for solar cells as an example, we performed CLSM correlative studies to quantify morphological and layer thickness changes during four stages of a thin-film compound synthesis. Using simple assumptions, we measured the micrometer-scale spatially resolved chemical composition of stacked precursor layers to predict the final material phases formed and predict relative device performance. The high spatial resolution, coupled with the ability to measure sizeable areas without influencing the synthesis at high speed, makes CLSM an excellent prospect for research and quality control tool for thin films.
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Affiliation(s)
- Ricardo G Poeira
- Department of Physics and Materials Science, University of Luxembourg, 41, rue du Brill, L-4422 Belvaux, Luxembourg
| | - Daniel Siopa
- Department of Physics and Materials Science, University of Luxembourg, 41, rue du Brill, L-4422 Belvaux, Luxembourg
| | - Pedro Anacleto
- INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Sascha Sadewasser
- INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - Phillip J Dale
- Department of Physics and Materials Science, University of Luxembourg, 41, rue du Brill, L-4422 Belvaux, Luxembourg
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Prates da Costa E, Huang X, Kübel C, Cheng X, Schladitz K, Hofmann A, Göbel U, Smarsly BM. Effects of Hydrothermal Treatment on Mesopore Structure and Connectivity in Doped Ceria-Zirconia Mixed Oxides. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:177-191. [PMID: 36562540 DOI: 10.1021/acs.langmuir.2c02366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Pore size and pore connectivity control diffusion-based transport in mesopores, a crucial property governing the performance of heterogeneous catalysts. In many cases, transition-metal oxide catalyst materials are prepared from molecular precursors involving hydrothermal treatment followed by heat treatment. Here, we investigate the effects of such a hydrothermal aftertreatment step, using an aqueous ammonia solution, on the disordered mesopore network of CexZr1-x-y-zYyLazO2-δ mixed oxides. This procedure is a common synthesis step in the preparation of such ceria-based oxygen storage materials applied in three-way catalysis, employed to improve the materials' thermal stability. We perform state-of-the-art Ar-physisorption analysis, especially advanced hysteresis scanning, to paint a detailed picture of the alterations in mesopore space caused by the hydrothermal aftertreatment and subsequent aging at 1050 °C. Furthermore, we investigate the network characteristics by electron tomography in combination with suitable statistical analysis, enabling a consistent interpretation of the desorption scans (physisorption). The results indicate that the hydrothermal aftertreatment enhances the mesopore connectivity of the continuous 3D network by widening pores and especially necks, hence facilitating accessibility to the particles' internal surface area and the ability to better withstand high temperatures.
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Affiliation(s)
- Eric Prates da Costa
- Institute of Physical Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 17, 35392Giessen, Germany
- Umicore AG & Co. KG, Rodenbacher Chaussee 4, 63457Hanau, Germany
| | - Xiaohui Huang
- Department of Materials and Earth Sciences, Technical University Darmstadt, Alarich-Weiss-Str. 2, 64287Darmstadt, Germany
| | - Christian Kübel
- Department of Materials and Earth Sciences, Technical University Darmstadt, Alarich-Weiss-Str. 2, 64287Darmstadt, Germany
| | - Xiaoyin Cheng
- Fraunhofer-Institut für Techno- und Wirtschaftsmathematik, Fraunhofer-Platz 1, 67663Kaiserslautern, Germany
| | - Katja Schladitz
- Fraunhofer-Institut für Techno- und Wirtschaftsmathematik, Fraunhofer-Platz 1, 67663Kaiserslautern, Germany
| | | | - Ulrich Göbel
- Umicore AG & Co. KG, Rodenbacher Chaussee 4, 63457Hanau, Germany
| | - Bernd M Smarsly
- Institute of Physical Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 17, 35392Giessen, Germany
- Center for Materials Research, Heinrich-Buff-Ring 16, 35392Giessen, Germany
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3
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Podgornik A. Characterization of a convection-based support microstructure through a flow resistance parameter. J Sep Sci 2022; 45:1984-1996. [PMID: 35218615 PMCID: PMC10138761 DOI: 10.1002/jssc.202100955] [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: 12/06/2021] [Revised: 02/04/2022] [Accepted: 02/06/2022] [Indexed: 11/11/2022]
Abstract
Modern convection-based supports differ substantially in pore size, porosity, and microstructure topology. Due to such variability, it is challenging to evaluate the contribution of a particular microstructure topology on flow resistance. We demonstrated that the flow resistance parameter (ϕ) introduced decades ago can be used as a criterion to evaluate the effect of microstructure topology on a pressure drop when the pore size is used as a characteristic support dimension. Furthermore, the ϕ value of simple cubic packing was calculated over the entire range of open porosity and compared to the ϕ values determined for pressure drop models derived for particular convection-based supports and experimental values of various convection-based supports from the literature. It was shown that different convection-based supports become clustered into distinct groups when plotted according to their ϕ and open porosity values, allowing their discrimination. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Aleš Podgornik
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, Večna pot 113, Ljubljana, Slovenia.,COBIK, Mirce 21, 5270 Ajdovščina, Slovenia
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Hochstrasser J, Juère E, Kleitz F, Wang W, Kübel C, Tallarek U. Insights into the intraparticle morphology of dendritic mesoporous silica nanoparticles from electron tomographic reconstructions. J Colloid Interface Sci 2021; 592:296-309. [PMID: 33676192 DOI: 10.1016/j.jcis.2021.02.069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/26/2021] [Accepted: 02/15/2021] [Indexed: 11/28/2022]
Abstract
HYPOTHESIS Although many synthetic pathways allow to fine-tune the morphology of dendritic mesoporous silica nanoparticles (DMSNs), the control of their particle size and mesopore diameter remains a challenge. Our study focuses on either increasing the mean particle size or adjusting the pore size distribution, changing only one parameter (particle or pore size) at a time. The dependence of key morphological features (porosity; pore shape and pore dimensions) on radial distance from the particle center has been investigated in detail. EXPERIMENTS Three-dimensional reconstructions of the particles obtained by scanning transmission electron microscopy (STEM) tomography were adapted as geometrical models for the quantification of intraparticle morphologies by radial porosity and chord length distribution analyses. Structural properties of the different synthesized DMSNs have been complementary characterized using TEM, SEM, nitrogen physisorption, and dynamic light scattering. FINDINGS The successful independent tuning of particle and pore sizes of the DMSNs could be confirmed by conventional analysis methods. Unique morphological features, which influence the uptake and release of guest molecules in biomedical applications, were uncovered from analyzing the STEM tomography-based reconstructions. It includes the quantification of structural hierarchy, identification of intrawall openings and pores, as well as the distinction of pore shapes (conical vs. cylindrical).
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Affiliation(s)
- Janika Hochstrasser
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Estelle Juère
- Department of Inorganic Chemistry - Functional Materials, Faculty of Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
| | - Freddy Kleitz
- Department of Inorganic Chemistry - Functional Materials, Faculty of Chemistry, University of Vienna, Währinger Strasse 42, 1090 Vienna, Austria
| | - Wu Wang
- Institute of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Christian Kübel
- Institute of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany; Department of Materials and Earth Sciences, Technische Universität Darmstadt, Alarich-Weiss-Strasse 2, 64287 Darmstadt, Germany
| | - Ulrich Tallarek
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
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5
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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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6
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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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7
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Teng X, Li F, Lu C. Visualization of materials using the confocal laser scanning microscopy technique. Chem Soc Rev 2020; 49:2408-2425. [PMID: 32134417 DOI: 10.1039/c8cs00061a] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The development of materials science always benefits from advanced characterizations. Currently, imaging techniques are of great technological importance in both fundamental and applied research on materials. In comparison to conventional visualization methods, confocal laser scanning microscopy (CLSM) is non-invasive, with macroscale and high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. In addition, CLSM allows rapid acquisition of longitudinal and cross-sectional images at any position in a material. Therefore, the CLSM-based visualization technique could provide direct and model-independent insight into material characterizations. This review summarizes the recent applications of CLSM in materials science. The current CLSM approaches for the visualization of surface structures, internal structures, spatial structures and reaction processes are discussed in detail. Finally, we provide our thoughts and predictions on the future development of CLSM in materials science. The purpose of this review is to guide researchers to build a suitable CLSM approach for material characterizations, and to open viable opportunities and inspirations for the development of new strategies aiming at the preparation of advanced materials. We hope that this review will be useful for a wide range of research communities of materials science, chemistry, and engineering.
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Affiliation(s)
- Xu Teng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering (BAICAS), State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
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8
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Mejía-Carmona K, Soares da Silva Burato J, Borsatto JVB, de Toffoli AL, Lanças FM. Miniaturization of liquid chromatography coupled to mass spectrometry. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2019.115735] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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Podgornik A. Pressure drop in liquid chromatography. J Sep Sci 2018; 42:72-88. [DOI: 10.1002/jssc.201800882] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/13/2018] [Accepted: 11/06/2018] [Indexed: 01/11/2023]
Affiliation(s)
- Aleš Podgornik
- Faculty of Chemistry and Chemical Technology; University of Ljubljana; Ljubljana Slovenia
- Center of Excellence for Biosensors; Instrumentation and Process Control - COBIK; Ajdovščina Slovenia
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10
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Axial heterogeneities in capillary ultrahigh pressure liquid chromatography columns: Chromatographic and bed morphological characterization. J Chromatogr A 2018; 1569:44-52. [DOI: 10.1016/j.chroma.2018.07.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/01/2018] [Accepted: 07/06/2018] [Indexed: 11/22/2022]
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11
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Yousefi N, Wong KKW, Hosseinidoust Z, Sørensen HO, Bruns S, Zheng Y, Tufenkji N. Hierarchically porous, ultra-strong reduced graphene oxide-cellulose nanocrystal sponges for exceptional adsorption of water contaminants. NANOSCALE 2018; 10:7171-7184. [PMID: 29620092 DOI: 10.1039/c7nr09037d] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Self-assembly of graphene oxide (GO) nanosheets into porous 3D sponges is a promising approach to exploit their capacity to adsorb contaminants while facilitating the recovery of the nanosheets from treated water. Yet, forming mechanically robust sponges with suitable adsorption properties presents a significant challenge. Ultra-strong and highly porous 3D sponges are formed using GO, vitamin C (VC), and cellulose nanocrystals (CNCs) - natural nanorods isolated from wood pulp. CNCs provide a robust scaffold for the partially reduced GO (rGO) nanosheets resulting in an exceptionally stiff nanohybrid. The concentration of VC as a reducing agent plays a critical role in tailoring the pore architecture of the sponges. By using excess amounts of VC, a unique hierarchical pore structure is achieved, where VC grains act as soft templates for forming millimeter-sized pores, the walls of which are also porous and comprised of micron-sized pores. The unique hierarchical pore structure ensures the interconnectivity of pores even at the core of large sponges as evidenced by micro and nano X-ray computed tomography. The unique pore architecture translates into an exceptional specific surface area for adsorption of a wide range of contaminants, such as dyes, heavy metals, pharmaceuticals and cyanotoxin from water.
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Affiliation(s)
- Nariman Yousefi
- Department of Chemical Engineering, McGill University, Montreal, QC, Canada.
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12
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da Silva CGA, Grespan Bottoli CB, Collins CH. 3-Dimensional X-ray microtomography methodology for characterization of monolithic stationary phases and columns for capillary liquid chromatography - A tutorial. Anal Chim Acta 2017; 991:30-45. [PMID: 29031297 DOI: 10.1016/j.aca.2017.08.040] [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: 02/04/2017] [Revised: 08/22/2017] [Accepted: 08/22/2017] [Indexed: 01/20/2023]
Abstract
In this tutorial we describe a fast, nondestructive, three-dimensional (3-D) view approach to be used in morphology characterization of capillary monoliths and columns by reconstruction from X-ray microtomography (XMT) obtained by acquiring projection images of the sample from a number of different directions. The method comprises imaging acquisition, imaging reconstruction using specific algorithms and imaging analysis by generation of a 3-D image of the sample from radiographic images. The 3-D images show the morphological data for bulk macropore space and skeleton connectivity of the monoliths and were compared with other images from imaging techniques such as scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) and with chromatographic performance. The 3-D XMT methodology is applicable for organic and inorganic capillary chromatographic monolithic materials and it allows the acquisition of many hundreds (in our case 1001 projections) of longitudinal and cross-sectional images in a single session, resolving morphological details with a 3D-view of the monolithic structure, inclusive inside the column in a sectional structure with volume (three dimensions) when compared to the sectional structure area (with only two dimensions) when using SEM and FESEM techniques.
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Affiliation(s)
- Carla G A da Silva
- Department of Chemistry, Federal University of Mato Grosso, 78060-900, Cuiabá, Brazil; Institute of Chemistry, University of Campinas, 13083-970, Campinas, Brazil.
| | | | - Carol H Collins
- Institute of Chemistry, University of Campinas, 13083-970, Campinas, Brazil.
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13
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Blue LE, Franklin EG, Godinho JM, Grinias JP, Grinias KM, Lunn DB, Moore SM. Recent advances in capillary ultrahigh pressure liquid chromatography. J Chromatogr A 2017; 1523:17-39. [PMID: 28599863 DOI: 10.1016/j.chroma.2017.05.039] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 11/28/2022]
Abstract
In the twenty years since its initial demonstration, capillary ultrahigh pressure liquid chromatography (UHPLC) has proven to be one of most powerful separation techniques for the analysis of complex mixtures. This review focuses on the most recent advances made since 2010 towards increasing the performance of such separations. Improvements in capillary column preparation techniques that have led to columns with unprecedented performance are described. New stationary phases and phase supports that have been reported over the past decade are detailed, with a focus on their use in capillary formats. A discussion on the instrument developments that have been required to ensure that extra-column effects do not diminish the intrinsic efficiency of these columns during analysis is also included. Finally, the impact of these capillary UHPLC topics on the field of proteomics and ways in which capillary UHPLC may continue to be applied to the separation of complex samples are addressed.
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Affiliation(s)
- Laura E Blue
- Process Development, Amgen Inc., Thousand Oaks, CA 91320, USA
| | - Edward G Franklin
- HPLC Research & Development, Restek Corp., Bellefonte, PA 16823, USA
| | - Justin M Godinho
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - James P Grinias
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ 08028, USA.
| | - Kaitlin M Grinias
- Department of Product Development & Supply, GlaxoSmithKline, King of Prussia, PA 19406, USA
| | - Daniel B Lunn
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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14
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Reising AE, Godinho JM, Jorgenson JW, Tallarek U. Bed morphological features associated with an optimal slurry concentration for reproducible preparation of efficient capillary ultrahigh pressure liquid chromatography columns. J Chromatogr A 2017; 1504:71-82. [PMID: 28511930 DOI: 10.1016/j.chroma.2017.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/20/2017] [Accepted: 05/04/2017] [Indexed: 11/30/2022]
Abstract
Column wall effects and the formation of larger voids in the bed during column packing are factors limiting the achievement of highly efficient columns. Systematic variation of packing conditions, combined with three-dimensional bed reconstruction and detailed morphological analysis of column beds, provide valuable insights into the packing process. Here, we study a set of sixteen 75μm i.d. fused-silica capillary columns packed with 1.9μm, C18-modified, bridged-ethyl hybrid silica particles slurried in acetone to concentrations ranging from 5 to 200mg/mL. Bed reconstructions for three of these columns (representing low, optimal, and high slurry concentrations), based on confocal laser scanning microscopy, reveal morphological features associated with the implemented slurry concentration, that lead to differences in column efficiency. At a low slurry concentration, the bed microstructure includes systematic radial heterogeneities such as particle size-segregation and local deviations from bulk packing density near the wall. These effects are suppressed (or at least reduced) with higher slurry concentrations. Concomitantly, larger voids (relative to the mean particle diameter) begin to form in the packing and increase in size and number with the slurry concentration. The most efficient columns are packed at slurry concentrations that balance these counteracting effects. Videos are taken at low and high slurry concentration to elucidate the bed formation process. At low slurry concentrations, particles arrive and settle individually, allowing for rearrangements. At high slurry concentrations, they arrive and pack as large patches (reflecting particle aggregation in the slurry). These processes are discussed with respect to column packing, chromatographic performance, and bed microstructure to help reinforce general trends previously described. Conclusions based on this comprehensive analysis guide us towards further improvement of the packing process.
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Affiliation(s)
- Arved E Reising
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Justin M Godinho
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, United States
| | - James W Jorgenson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, United States.
| | - Ulrich Tallarek
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
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15
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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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16
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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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17
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Tanaka N. Introduction to “Monolithic columns in high-performance liquid chromatography” by G. Guiochon [J. Chromatogr. A 1168 (2007) 101–168]. J Chromatogr A 2016; 1446:15-6. [DOI: 10.1016/j.chroma.2015.10.084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 09/29/2015] [Accepted: 10/25/2015] [Indexed: 10/22/2022]
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18
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Reising AE, Godinho JM, Hormann K, Jorgenson JW, Tallarek U. Larger voids in mechanically stable, loose packings of 1.3μm frictional, cohesive particles: Their reconstruction, statistical analysis, and impact on separation efficiency. J Chromatogr A 2016; 1436:118-32. [PMID: 26858113 DOI: 10.1016/j.chroma.2016.01.068] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/21/2016] [Accepted: 01/24/2016] [Indexed: 12/23/2022]
Abstract
Lateral transcolumn heterogeneities and the presence of larger voids in a packing (comparable to the particle size) can limit the preparation of efficient chromatographic columns. Optimizing and understanding the packing process provides keys to better packing structures and column performance. Here, we investigate the slurry-packing process for a set of capillary columns packed with C18-modified, 1.3μm bridged-ethyl hybrid porous silica particles. The slurry concentration used for packing 75μm i.d. fused-silica capillaries was increased gradually from 5 to 50mg/mL. An intermediate concentration (20mg/mL) resulted in the best separation efficiency. Three capillaries from the set representing low, intermediate, and high slurry concentrations were further used for three-dimensional bed reconstruction by confocal laser scanning microscopy and morphological analysis of the bed structure. Previous studies suggest increased slurry concentrations will result in higher column efficiency due to the suppression of transcolumn bed heterogeneities, but only up to a critical concentration. Too concentrated slurries favour the formation of larger packing voids (reaching the size of the average particle diameter). Especially large voids, which can accommodate particles from>90% of the particle size distribution, are responsible for a decrease in column efficiency at high slurry concentrations. Our work illuminates the increasing difficulty of achieving high bed densities with small, frictional, cohesive particles. As particle size decreases interparticle forces become increasingly important and hinder the ease of particle sliding during column packing. While an optimal slurry concentration is identified with respect to bed morphology and separation efficiency under conditions in this work, our results suggest adjustments of this concentration are required with regard to particle size, surface roughness, column dimensions, slurry liquid, and external effects utilized during the packing process (pressure protocol, ultrasound, electric fields).
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Affiliation(s)
- Arved E Reising
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - Justin M Godinho
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, United States
| | - Kristof Hormann
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
| | - James W Jorgenson
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, United States.
| | - Ulrich Tallarek
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
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19
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Hormann K, Baranau V, Hlushkou D, Höltzel A, Tallarek U. Topological analysis of non-granular, disordered porous media: determination of pore connectivity, pore coordination, and geometric tortuosity in physically reconstructed silica monoliths. NEW J CHEM 2016. [DOI: 10.1039/c5nj02814k] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Different approaches are applied and compared, which are universally applicable to quantify pore coordination, pore and pore-throat connectivity, and geometric tortuosity.
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Affiliation(s)
- Kristof Hormann
- Department of Chemistry
- Philipps-Universität Marburg
- D-35032 Marburg
- Germany
| | - Vasili Baranau
- Department of Chemistry
- Philipps-Universität Marburg
- D-35032 Marburg
- Germany
| | - Dzmitry Hlushkou
- Department of Chemistry
- Philipps-Universität Marburg
- D-35032 Marburg
- Germany
| | - Alexandra Höltzel
- Department of Chemistry
- Philipps-Universität Marburg
- D-35032 Marburg
- Germany
| | - Ulrich Tallarek
- Department of Chemistry
- Philipps-Universität Marburg
- D-35032 Marburg
- Germany
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20
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Müllner T, Zankel A, Lv Y, Svec F, Höltzel A, Tallarek U. Assessing structural correlations and heterogeneity length scales in functional porous polymers from physical reconstructions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:6009-6013. [PMID: 26314251 DOI: 10.1002/adma.201502332] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 07/16/2015] [Indexed: 06/04/2023]
Abstract
A general, model-free, quantitative approach to the key morphological properties of a porous polymer monolith is presented. After 3D reconstruction, image-based analysis delivers detailed spatial and spatially correlated information on the structural heterogeneities in the void space and the polymer skeleton. Identified heterogeneities, which limit the monolith's performance in targeted applications, are traced back to the preparation process.
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Affiliation(s)
- Tibor Müllner
- Philipps-Universität Marburg, Department of Chemistry, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Armin Zankel
- Graz University of Technology, NAWI Graz, Institute for Electron Microscopy and Nanoanalysis and Center for Electron Microscopy, Steyrergasse 17, 8010, Graz, Austria
| | - Yongqin Lv
- International Research Center for Soft Matter, Beijing University of Chemical Technology, 100029, Beijing, China
| | - Frantisek Svec
- International Research Center for Soft Matter, Beijing University of Chemical Technology, 100029, Beijing, China
| | - Alexandra Höltzel
- Philipps-Universität Marburg, Department of Chemistry, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
| | - Ulrich Tallarek
- Philipps-Universität Marburg, Department of Chemistry, Hans-Meerwein-Strasse 4, 35032, Marburg, Germany
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21
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Stoeckel D, Kübel C, Loeh MO, Smarsly BM, Tallarek U. Morphological Analysis of Physically Reconstructed Silica Monoliths with Submicrometer Macropores: Effect of Decreasing Domain Size on Structural Homogeneity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:7391-7400. [PMID: 25654337 DOI: 10.1021/la5046018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Silica monoliths are increasingly used as fixed-bed supports in separation and catalysis because their bimodal pore space architecture combines excellent mass transport properties with a large surface area. To optimize their performance, a quantitative relationship between morphology and transport characteristics has to be established, and synthesis conditions that lead to a desired morphology optimized for a targeted application must be identified. However, the effects of specific synthesis parameters on the structural properties of silica monoliths are still poorly understood. An important question is how far the macropore and domain size can be reduced without compromising the structural homogeneity. We address this question with quantitative morphological data derived for a set of eight macroporous-mesoporous silica monoliths with an average macropore size (d(macro)) of between 3.7 and 0.1 μm, prepared following an established route involving the sol-gel transition and phase separation. The macropore space of the silica monolith samples is reconstructed using focused ion beam scanning electron microscopy followed by a quantitative assessment of geometrical and topological properties based on chord length distributions (CLDs) and branch-node analysis of the pore network, respectively. We observe a significant increase in structural heterogeneity, indicated by a decrease in the parameter k derived from fitting a k-gamma function to the CLDs, when d(macro) reaches the submicrometer range. The compromised structural homogeneity of silica monoliths with submicrometer macropores could possibly originate from early structural freezing during the competitive processes of sol-gel transition and phase separation. It is therefore questionable if the common approach of reducing the morphological features of silica monoliths into the submicrometer regime by changing the point of sol-gel transition can be successful. Alternative strategies and a better understanding of the involved competitive processes should be the focus of future research.
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Affiliation(s)
- Daniela Stoeckel
- †Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
- ‡Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 58, 35392 Gießen, Germany
| | - Christian Kübel
- §Institute of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Marc O Loeh
- ‡Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 58, 35392 Gießen, Germany
| | - Bernd M Smarsly
- ‡Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 58, 35392 Gießen, Germany
| | - Ulrich Tallarek
- †Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
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22
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Meinusch R, Hormann K, Hakim R, Tallarek U, Smarsly BM. Synthesis and morphological characterization of phenyl-modified macroporous–mesoporous hybrid silica monoliths. RSC Adv 2015. [DOI: 10.1039/c4ra16519e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We present a comprehensive approach to characterize the one-pot synthesis, macropore space morphology, and chromatographic performance of phenyl-modified macro–mesoporous silica monoliths.
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Affiliation(s)
- Rafael Meinusch
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
| | - Kristof Hormann
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Romana Hakim
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
- Thermo Fisher Scientific
| | - Ulrich Tallarek
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Bernd M. Smarsly
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
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23
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Hormann K, Tallarek U. Mass transport properties of second-generation silica monoliths with mean mesopore size from 5 to 25nm. J Chromatogr A 2014; 1365:94-105. [DOI: 10.1016/j.chroma.2014.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/03/2014] [Accepted: 09/03/2014] [Indexed: 10/24/2022]
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24
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Müllner T, Zankel A, Svec F, Tallarek U. Large-Volume Reconstruction of Porous Polymers for Simultaneous Analysis of Micron and Submicron Morphological Features. CHEM-ING-TECH 2014. [DOI: 10.1002/cite.201450623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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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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26
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Aggarwal P, Asthana V, Lawson JS, Tolley HD, Wheeler DR, Mazzeo BA, Lee ML. Correlation of chromatographic performance with morphological features of organic polymer monoliths. J Chromatogr A 2014; 1334:20-9. [PMID: 24569008 DOI: 10.1016/j.chroma.2014.01.056] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 01/17/2014] [Accepted: 01/20/2014] [Indexed: 11/27/2022]
Abstract
Monoliths are considered to be a low pressure alternative to particle packed columns for liquid chromatography (LC). However, the chromatographic performance of organic monoliths, in particular, has still not reached the level of particle packed columns. Since chromatographic performance can be attributed to morphological features of the monoliths, in-situ characterization of the monolith structure in three dimensions would provide valuable information that could be used to help improve performance. In this work, serial sectioning and imaging were performed with a dual-beam scanning electron microscope for reconstruction and quantitative characterization of poly(ethylene glycol) diacrylate (PEGDA) monoliths inside a capillary column. Chord lengths, homogeneity factors, porosities and tortuosities were calculated from three-dimensional (3D) reconstructions of two PEGDA monoliths. Chromatographic efficiency was better for the monolith with smaller mean chord length (i.e., 5.23μm), porosity (i.e., 0.49) and tortuosity (i.e., 1.50) compared to values of 5.90μm, 0.59 and 2.34, respectively, for the other monolithic column. Computational prediction of tortuosity (2.32) was found to be in agreement with the experimentally measured value (2.34) for the same column. The monoliths were found to have significant radial heterogeneity since the homogeneity factor decreased from 5.39 to 4.89 (from center to edge) along the column radius.
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Affiliation(s)
- Pankaj Aggarwal
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA
| | | | - John S Lawson
- Department of Statistics, Brigham Young University, Provo, UT 84602, USA
| | - H Dennis Tolley
- Department of Statistics, Brigham Young University, Provo, UT 84602, USA
| | - Dean R Wheeler
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Brian A Mazzeo
- Department of Electrical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - Milton L Lee
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
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27
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Vázquez M, Moore D, He X, Ben Azouz A, Nesterenko E, Nesterenko P, Paull B, Brabazon D. Focussed ion beam serial sectioning and imaging of monolithic materials for 3D reconstruction and morphological parameter evaluation. Analyst 2014; 139:99-104. [DOI: 10.1039/c3an01827j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Bruns S, Franklin EG, Grinias JP, Godinho JM, Jorgenson JW, Tallarek U. Slurry concentration effects on the bed morphology and separation efficiency of capillaries packed with sub-2μm particles. J Chromatogr A 2013; 1318:189-97. [DOI: 10.1016/j.chroma.2013.10.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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29
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Hormann K, Tallarek U. Analytical silica monoliths with submicron macropores: current limitations to a direct morphology-column efficiency scaling. J Chromatogr A 2013; 1312:26-36. [PMID: 24041508 DOI: 10.1016/j.chroma.2013.08.087] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 08/22/2013] [Accepted: 08/22/2013] [Indexed: 12/01/2022]
Abstract
Shrinking the structural elements of a particulate bed or monolith (i.e., the particle or domain size) yields more efficient columns only when the homogeneity of the bed can be conserved in that process. We investigate this complex issue for a set of 2nd generation analytical silica monoliths with macropores reaching submicron dimensions using chromatographic methods, mercury intrusion porosimetry, scanning electron microscopy, and confocal laser scanning microscopy (CLSM), and present eddy dispersion simulations and a chord length distribution analysis for the CLSM-based physical reconstructions at macropore resolution. The combined results allow us to identify relevant morphological advances made from 1st to 2nd generation monoliths and additionally highlight the current limitations to a direct morphology-efficiency scaling with respect to the performance that can be accomplished in HPLC practice with these columns. Whereas the improvement in radial homogeneity from 1st to 2nd generation silica monoliths is represented by a dramatic increase in column efficiency, the further reduction of macropore size in the 2nd generation monoliths does not lead to the expected improvement of plate height data, although these monoliths realize submicron macropores at a simultaneously conserved bulk macropore space homogeneity and negligible radial heterogeneity. Our study implies that limitations to further improved column efficiency arise from the intrinsic border effects of the used 4.6mm i.d. analytical columns. This includes the sample distribution onto the monoliths and asynchronous sample collection through the endfittings at the column inlet and outlet, respectively. Only when these effects are reduced will additionally improved 2nd generation monoliths live up to column efficiencies, which are envisioned for them based on their morphological properties.
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Affiliation(s)
- Kristof Hormann
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
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30
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Loh KC, Vasudevan V. Response to "comments on 'Hydrodynamic and dispersion behavior in a non-porous silica monolith through fluid dynamic study of a computational mimic reconstructed from sub-micro-tomographic scans"'. J Chromatogr A 2013; 1302:208-12. [PMID: 23845756 DOI: 10.1016/j.chroma.2013.05.077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 05/29/2013] [Indexed: 11/30/2022]
Abstract
We respond to the comments made by Hlushkou et al. (2013) [1] (JCA-13-207) to our earlier work [J. Chromatogr. A 1274 (2013) 65], wherein the authors have questioned the validity of our reconstruction of the bulk macropore space in a silica monolith and challenged the interpretations from subsequent computational fluid dynamic simulations. We provide an explanation as to why a monotonic trend in external porosity values cannot be expected with decreasing scanning resolutions. The observed deviations of the pore and skeleton size distributions from those in literature are explained based on the differences in methods used to calculate these distributions. The difference in the scaled axial velocity frequency distributions is explained based on the assumptions made and the distributions are redrawn to reflect the said assumptions. The normalized transient diffusion (peak parking) and dispersion simulations are repeated with a higher resolution of detection planes to measure the variance of spreading pulse, thereby providing an explanation for the anomalies pointed out in our earlier work. Finally, we explain our comparison of the computational expenses with previous work as a study of the trade-off in accuracy that results from the lower resolution scan and use of commercial CFD packages.
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Affiliation(s)
- Kai-Chee Loh
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585, Singapore.
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31
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Comments on "hydrodynamic and dispersion behavior in a non-porous silica monolith through fluid dynamic study of a computational mimic reconstructed from sub-micro-tomographic scans". J Chromatogr A 2013; 1302:205-7. [PMID: 23806353 DOI: 10.1016/j.chroma.2013.05.071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 05/29/2013] [Indexed: 11/23/2022]
Abstract
We comment on a recently published paper by Loh and Vasudevan [J. Chromatogr. A 1274 (2013) 65], which reported the physical reconstruction of the bulk macropore space of an analytical silica monolith by X-ray computed microtomography and the subsequent computational fluid dynamics simulations of flow and mass transport in the reconstructed monolith model. Loh and Vasudevan claim that their combined reconstruction and simulation approach offers a significant reduction of computational expenses without significant loss in accuracy in characterizing the macropore space heterogeneity of the monolith and predicting its transport properties. We challenge their claim and question the validity and validation of their results by discussing the employed scanning resolution, the characterization of macropore space heterogeneities, the interpretation of the simulated dispersion data, as well as the comparison of computational expenses with previous work.
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32
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Comparison of first and second generation analytical silica monoliths by pore-scale simulations of eddy dispersion in the bulk region. J Chromatogr A 2013; 1303:28-38. [DOI: 10.1016/j.chroma.2013.06.039] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/12/2013] [Accepted: 06/14/2013] [Indexed: 11/24/2022]
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33
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Laher M, Causon TJ, Buchberger W, Hild S, Nischang I. Assessing the Nanoscale Structure and Mechanical Properties of Polymer Monoliths used for Chromatography. Anal Chem 2013; 85:5645-9. [DOI: 10.1021/ac401303k] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martin Laher
- Institute of Polymer Science, Johannes Kepler University Linz, Altenberger Strasse
69, A-4040 Linz, Austria
| | - Tim J. Causon
- Institute of Analytical Chemistry, Johannes Kepler University Linz, Altenberger Strasse
69, A-4040 Linz, Austria
| | - Wolfgang Buchberger
- Institute of Analytical Chemistry, Johannes Kepler University Linz, Altenberger Strasse
69, A-4040 Linz, Austria
| | - Sabine Hild
- Institute of Polymer Science, Johannes Kepler University Linz, Altenberger Strasse
69, A-4040 Linz, Austria
| | - Ivo Nischang
- Institute of Polymer Chemistry, Johannes Kepler University Linz, Welser Strasse 42,
A-4060 Leonding, Austria
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34
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Porous polymer monoliths: Morphology, porous properties, polymer nanoscale gel structure and their impact on chromatographic performance. J Chromatogr A 2013; 1287:39-58. [DOI: 10.1016/j.chroma.2012.11.016] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 11/02/2012] [Accepted: 11/06/2012] [Indexed: 11/20/2022]
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35
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Liao T, Guo Z, Li J, Liu M, Chen Y. One-step packing of anti-voltage photonic crystals into microfluidic channels for ultra-fast separation of amino acids and peptides. LAB ON A CHIP 2013; 13:706-713. [PMID: 23254760 DOI: 10.1039/c2lc40720e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Packing of stable and crack-free photonic crystals (PCs) into micro channels is a prerequisite for ideal separation, but often takes several days and many steps, including assembly and immobilization. This work was dedicated to finding a fast, one-step solution. Simply by heating and blowing away the vapor, the packing of silica PCs into micro channels by classic evaporation-induced assembly was greatly accelerated and could unite the immobilization into one step. An apt method was thus established, which was able to pack 2 cm PCs into microfluidic channels in 15 min, saving a lot of time. The packed PCs showed no evident cracks along the borders of their continuous domain, therefore they are capable of withstanding an anti-electrical field at 2000 V cm(-1) for 5 h and storage in water for 2 months. This enables ultra-fast separation of amino acids along a 2.5 mm PC in 4 s, and peptides along a 10 mm PC in 12 s. The separation was highly efficient and reproducible, with a 300 nm plate height and 0.24%-0.35% relative standard deviation of migration time. This one-step approach is extendable to other gelling particles, and the resulted stable, crack-free PCs would have large potential in ultra-fast separation of other analytes.
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Affiliation(s)
- Tao Liao
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, PR China
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36
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Hydrodynamic and dispersion behavior in a non-porous silica monolith through fluid dynamic study of a computational mimic reconstructed from sub-micro-tomographic scans. J Chromatogr A 2013; 1274:65-76. [DOI: 10.1016/j.chroma.2012.11.085] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 10/19/2012] [Accepted: 11/26/2012] [Indexed: 11/22/2022]
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37
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Bruns S, Stoeckel D, Smarsly BM, Tallarek U. Influence of particle properties on the wall region in packed capillaries. J Chromatogr A 2012; 1268:53-63. [DOI: 10.1016/j.chroma.2012.10.027] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 10/10/2012] [Accepted: 10/10/2012] [Indexed: 10/27/2022]
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38
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Daneyko A, Hlushkou D, Khirevich S, Tallarek U. From random sphere packings to regular pillar arrays: Analysis of transverse dispersion. J Chromatogr A 2012; 1257:98-115. [DOI: 10.1016/j.chroma.2012.08.024] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 08/02/2012] [Accepted: 08/05/2012] [Indexed: 11/26/2022]
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39
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Gritti F, Guiochon G. A revisit of the concept of external film mass transfer resistance in the packed beds used in high-performance liquid chromatography. Chem Eng Sci 2012. [DOI: 10.1016/j.ces.2012.01.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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40
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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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41
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Morphology and separation efficiency of a new generation of analytical silica monoliths. J Chromatogr A 2012; 1222:46-58. [DOI: 10.1016/j.chroma.2011.12.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/01/2011] [Accepted: 12/04/2011] [Indexed: 11/21/2022]
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42
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Arrua RD, Causon TJ, Hilder EF. Recent developments and future possibilities for polymer monoliths in separation science. Analyst 2012; 137:5179-89. [DOI: 10.1039/c2an35804b] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Kutter JP. Liquid phase chromatography on microchips. J Chromatogr A 2012; 1221:72-82. [DOI: 10.1016/j.chroma.2011.10.044] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 10/12/2011] [Accepted: 10/17/2011] [Indexed: 01/12/2023]
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44
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Daneyko A, Khirevich S, Höltzel A, Seidel-Morgenstern A, Tallarek U. From random sphere packings to regular pillar arrays: Effect of the macroscopic confinement on hydrodynamic dispersion. J Chromatogr A 2011; 1218:8231-48. [DOI: 10.1016/j.chroma.2011.09.039] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/06/2011] [Accepted: 09/13/2011] [Indexed: 11/16/2022]
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45
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Structure–transport correlation for the diffusive tortuosity of bulk, monodisperse, random sphere packings. J Chromatogr A 2011; 1218:6489-97. [DOI: 10.1016/j.chroma.2011.07.066] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 07/11/2011] [Accepted: 07/12/2011] [Indexed: 11/17/2022]
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46
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Morphological analysis of physically reconstructed capillary hybrid silica monoliths and correlation with separation efficiency. J Chromatogr A 2011; 1218:5187-94. [DOI: 10.1016/j.chroma.2011.05.090] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 05/23/2011] [Accepted: 05/24/2011] [Indexed: 11/20/2022]
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47
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Hlushkou D, Bruns S, Seidel-Morgenstern A, Tallarek U. Morphology-transport relationships for silica monoliths: From physical reconstruction to pore-scale simulations. J Sep Sci 2011; 34:2026-37. [DOI: 10.1002/jssc.201100158] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 04/18/2011] [Accepted: 04/18/2011] [Indexed: 11/10/2022]
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48
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Hara T, Mascotto S, Weidmann C, Smarsly BM. The effect of hydrothermal treatment on column performance for monolithic silica capillary columns. J Chromatogr A 2011; 1218:3624-35. [DOI: 10.1016/j.chroma.2011.04.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 03/21/2011] [Accepted: 04/04/2011] [Indexed: 11/30/2022]
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49
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Ghanem A, Ikegami T. Recent advances in silica-based monoliths: Preparations, characterizations and applications. J Sep Sci 2011; 34:1945-57. [DOI: 10.1002/jssc.201100086] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 02/10/2011] [Accepted: 02/14/2011] [Indexed: 12/19/2022]
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50
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Bruns S, Tallarek U. Physical reconstruction of packed beds and their morphological analysis: Core–shell packings as an example. J Chromatogr A 2011; 1218:1849-60. [DOI: 10.1016/j.chroma.2011.02.013] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 01/28/2011] [Accepted: 02/05/2011] [Indexed: 11/30/2022]
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