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Chen B, Zhu Y, Ma S, Zhao B, Feng F. A semi-packed gas chromatographic column with staggered elliptic cylindrical post arrays. Analyst 2024; 149:1579-1585. [PMID: 38288594 DOI: 10.1039/d3an02016a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
A semi-packed gas chromatographic column has the advantages of high specific surface area and low column pressure. We report that the stagnation regions formed in the adjacent posts along the channel of the semi-packed columns can decrease the area and height of chromatographic peaks, which makes it difficult to detect low-concentration mixed gases. A semi-packed column with staggered elliptic cylindrical post arrays (SC-S) made using a micro-electro-mechanical system technique is presented, and the separation performance of SC-S is compared with that of a semi-packed column with aligned elliptic cylindrical post arrays (SC-A). The simulation results show that the width of stagnation regions in SC-S is 86.89% smaller than that in SC-A. The experimental results indicate that the area and height of chromatographic peaks increased as stagnation regions reduced. In the separation of the alkane mixture from C8 through C10 with 10 ppm concentration, the chromatographic peak of decane was hardly identified in SC-A while the chromatographic peak in SC-S was still clearly visible. The chromatographic peak heights of octane and nonane were increased by 65.06% and 130.00%, respectively, in SC-S. The peak areas of octane and nonane were increased by 120.45% and 168.18%, respectively.
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Affiliation(s)
- Boxin Chen
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuchen Zhu
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shaojie Ma
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Zhao
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Feng
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Adrover A, Venditti C, Desmet G. An alternative general model for the effective longitudinal diffusion in chromatographic beds filled with ordered porous particles. J Chromatogr A 2024; 1715:464598. [PMID: 38171067 DOI: 10.1016/j.chroma.2023.464598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 12/13/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024]
Abstract
The two-zone moment-analysis method for the determination of the dispersion tensor in hierarchical retentive porous media has been adopted to compute and model the effective longitudinal diffusion Deff, or equivalently the B-term band broadening, in chromatographic beds filled with ordered porous particles. On the one hand, this approach offers accurate numerical results for Deff while keeping computational expenses low. On the other hand, it also gives direct insight for the analytical modelling, readily revealings the two main essential quantities (resp. referred to as the mobile-zone and stationary-zone effective diffusion factors γm and γs) that contribute to Deff. Modelling these two main parameters provided us with two new analytical models for Deff: a general one, valid for diluted and concentrated packings and accurate in the whole range of relevant intra-particle diffusion coefficient Dpz, and an approximate one, reliable for diluted packings and accurate also for concentrated packings with low to intermediate values of Dpz. The large advantage of both models is that they do not need any fitting parameter because all the required information is incorporated into the experimentally accessible geometric obstruction factor in the mobile phase originating from the tortuosity of the through-pore space (limiting case of fully solid particles without any retention). These models hence serve as an alternative to the Effective Medium Theory (EMT) models used so far in the literature. To validate the theory, five ordered geometries have been investigated. The accuracy of the general model proposed has been quantified and found to be comparable with that of the 3rd order approximate Torquato model for four geometries, even for macro-porosities close to the close-packing limit. The case of a 2-d triangular array of ellipsoidal particles with different elongations is also investigated to show the general validity and applicability of the models.
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Affiliation(s)
- Alessandra Adrover
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy.
| | - Claudia Venditti
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
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3
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Moussa A, Huygens B, Venditti C, Adrover A, Desmet G. Theoretical computation of the band broadening in micro-pillar array columns. J Chromatogr A 2024; 1715:464607. [PMID: 38154258 DOI: 10.1016/j.chroma.2023.464607] [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: 10/14/2023] [Revised: 12/08/2023] [Accepted: 12/23/2023] [Indexed: 12/30/2023]
Abstract
We have investigated the possibility to establish a theoretical plate height expression for the band broadening in the most widely used micro-pillar array column format, i.e., a cylindrical pillar array wherein the pillar walls and the channel bottom are coated with a thin layer of meso‑porous material. Assuming isotropic diffusion in the shell-layer, it was found that the vertical diffusive transport along the porous shell-layer covering the pillar walls significantly suppresses the band broadening originating from the vertical migration velocity gradients. As the vertical transport in the shell-layer increases linearly with the retention equilibrium constant K, this leads to an anomalous dependency on the retention factor. Indeed, instead of increasing with k'' and following the classic (1+ak''+bk''2)/(1 + k'')2-dependency governing a classic Taylor-Aris system, the variation of the mobile zone mass transfer resistance term hCm in a 3D pillar array with bottom-wall retention goes through a maximum (resp. factor 1.5 (k''=4) and 2 (k''=16) difference between observed and classic Taylor-Aris behaviour). This effect increases with increasing pillar heights and increasing reduced velocities. Because of this complex k''-dependency, it proves very cumbersome to establish a general plate height equation covering all conditions. Instead, a plate height expression was established that is limited up to k''=4, but remains accurate for higher k''-values for cases where the ratio of pillar height over inter-pillar distance remains below 5. It can however be anticipated the proposed analytical model is only valid in a rather limited range around the presently considered external porosity of ε=0.5.
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Affiliation(s)
- Ali Moussa
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Bram Huygens
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Claudia Venditti
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Alessandra Adrover
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.
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4
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Huygens B, Venditti C, Adrover A, Desmet G. Nonadditivity and Nonlinearity of Mobile and Stationary Zone Mass Transfer Resistances in Chromatography. Anal Chem 2023; 95:15199-15207. [PMID: 37791982 DOI: 10.1021/acs.analchem.3c01971] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Using a two-zone moment analysis (TZMA) method based on Brenner's generalized dispersion theory for two-dimensional (2D) and three-dimensional (3D) periodic media, we investigated the mechanisms for dispersion in particulate media for liquid chromatography. This was done using a set of plate height data covering an unprecedented wide range of retention factors, diffusion coefficients, and velocities, all computed with unequaled accuracy. Applying Giddings' additivity test, based on alternatingly making the diffusion coefficient in the mobile and stationary zones infinitely large, the dispersion data clearly indicate a lack of additivity. Although this lack could be directly understood by identifying the existence of multiple parallel mass transfer paths, the additivity assumption interestingly overestimates the true C term band broadening (typically by more than 10%, depending on conditions and dimensionality of the system). However, Giddings originally asserted the occurrence of parallel paths would always lead to an underestimation of the dispersion. The origin of the lack of additivity is analyzed in detail and qualitatively explained. Finally, we also established a generic framework for the modeling of the effect of the reduced velocity and the retention coefficient on the C term in ordered chromatographic media. This led to the introduction of a new expression for the mobile zone mass transfer term, which, unlike the currently used literature expression, contains the complete k″ dependency.
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Affiliation(s)
- Bram Huygens
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Claudia Venditti
- Department of Chemical Engineering, Materials, Environment, Sapienza Università di Roma, Via Eudossiana 18, 00184 Rome, Italy
| | - Alessandra Adrover
- Department of Chemical Engineering, Materials, Environment, Sapienza Università di Roma, Via Eudossiana 18, 00184 Rome, Italy
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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5
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Venditti C, Huygens B, Desmet G, Adrover A. Moment analysis for predicting effective transport properties in hierarchical retentive porous media. J Chromatogr A 2023; 1703:464099. [PMID: 37271084 DOI: 10.1016/j.chroma.2023.464099] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/09/2023] [Accepted: 05/22/2023] [Indexed: 06/06/2023]
Abstract
We report on a new homogenization approach to solve, with drastically improved speed and accuracy, the general advection-diffusion equation in hierarchical porous media with localized diffusion and adsorption/desorption processes, thus opening the way to a much deeper understanding of the band broadening process in chromatographic systems. The proposed robust and efficient moment-based approach allows us to compute the exact local and integral concentration moments and hence provides exact solutions for the effective velocity and dispersion coefficients of migrating solute particles. Innovative to the proposed method is also that it not only produces the exact effective transport parameters of the long-time asymptotic solution, but also their entire transient. The analysis of the transient behaviour can be used, for example, to properly identify the time and length scales needed to achieve the macro-transport conditions. If the hierarchical porous media can be represented as the periodic repetition of a unit lattice cell, the method only requires the solution of the time-dependent advection-diffusion equations for the zeroth order and first-order exact local moments, exclusively on the unit cell. This implies an enormous reduction of the computational efforts and a significant improvement of the accuracy of the results when compared to the direct numerical simulation (DNS) approaches which require flow domains that are long enough to achieve steady-state conditions, and hence often cover tens to hundreds of unit cells. The reliability of the proposed method is verified by comparing its predictions with DNS results, in one, two and three dimensions, in both transient and asymptotic conditions. The influence of top and bottom no-slip walls on the separation performance of chromatographic columns with micromachined porous and nonporous pillars is discussed in detail.
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Affiliation(s)
- Claudia Venditti
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy
| | - Bram Huygens
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Alessandra Adrover
- Dipartimento di Ingegneria Chimica Materiali Ambiente, Sapienza Università di Roma, Italy.
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6
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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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7
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Gritti F, Nawada S. On the road towards highly efficient and large volume three-dimensional-printed liquid chromatography columns ? J Sep Sci 2022; 45:3232-3240. [PMID: 35143712 DOI: 10.1002/jssc.202100962] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/20/2022] [Accepted: 01/26/2022] [Indexed: 11/11/2022]
Abstract
The current performance of commercially packed LC columns is limited by the random structure of the packed bed and by the wall-to-center heterogeneity of its structure. The minimum reduced plate heights observed are not smaller than 1.4 whereas they could theoretically be as low as 0.1 for dense and perfectly ordered packings of spheres. To bridge this gap, a wide inner diameter column with an ordered macroporous structure is printed in three dimensions by stereolithography of poly(ethylene glycol diacrylate) resin. Feature sizes below 100 μm are achieved by combining conventional polymer stereolithography with photolithography using photomasks. A layer-by-layer polymerization is performed by alternating two distinct photomasks having horizontally and vertically oriented patterns. Despite the inevitable printing imperfections, minimum reduced plate heights around unity are measured for non-retained analytes. The next challenges for the successful printing of highly efficient and large volume LC columns are threefold: reducing the feature size down to below 10 μm, keeping minimum the unevenness of the flow channel dimensions, and tackling additive manufacturing of silica aerogels at such small feature sizes for higher mechanical stability and broader range of retention/selectivity than those delivered by polymer materials. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Fabrice Gritti
- Waters Corporation, Core Research/Fundamentals, 34 Maple Street, Milford, MA, 01757, USA
| | - Suhas Nawada
- Universiteit van Amsterdam, Van 't Hoff Institute for Molecular Sciences, Science Park 904, Amsterdam, 1098, The Netherlands
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8
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Wang X, Zhu J, Yang C, Qin F, Zhang B. Segmented Microfluidics-Based Packing Technology for Chromatographic Columns. Anal Chem 2021; 93:8450-8458. [PMID: 34111926 DOI: 10.1021/acs.analchem.1c00545] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nanoflow liquid chromatography-mass spectrometry (NanoLC-MS) has become the method of choice for the analysis of complex biological systems, especially when the available sample amount is limited. The preparation of high-performance capillary columns for nanoLC use is still a technical challenge. Here, we report a segmented microfluidic method for the preparation of packed capillary columns, where liquid segments were used as soft, dynamic, and well-dispersed slurry reservoirs for carrying and delivering micrometer packing particles. Based on this microfluidic packing technology, the column bed was assembled layer-by-layer at a 50 μm resolution, and ultralong capillary columns of 3, 5, and 10 m were fabricated in such a manner. The microfluidically packed columns demonstrated excellent separation efficiencies of 116 000 plates/m. The higher efficiencies obtained at higher slurry concentrations also indicate that a high-quality packed bed can be obtained without sacrificing the packing speed. Kinetic performance limit analysis shows that the microfluidic packed columns have higher peak capacity production efficiency in the high-resolution region, presenting an improved separation impedance of 2800, which is significantly better than columns packed with the conventional slurry packing method. In comparison with a commercial nanoLC column, a 5 m long microfluidic packed column was evaluated for proteomic analysis using a standard HeLa protein digest and presented 261% improvement in peptide identification capability, resulting in significantly enhanced protein identification confidence.
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Affiliation(s)
- Xiaofei Wang
- Department of Chemistry and The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jue Zhu
- Department of Chemistry and The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Chenyuhu Yang
- Department of Chemistry and The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Fei Qin
- Xiamen Medical College, Xiamen 361023, China
| | - Bo Zhang
- Department of Chemistry and The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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9
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Fujiwara T, Funatsu T, Tsunoda M. Fast analysis using pillar array columns: Quantification of branched-chain α-keto acids in human plasma samples. J Pharm Biomed Anal 2021; 198:114019. [PMID: 33725587 DOI: 10.1016/j.jpba.2021.114019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/06/2021] [Accepted: 03/06/2021] [Indexed: 10/22/2022]
Abstract
Branched-chain α-keto acids (BCKAs, namely, α-ketoisovaleric acid (KIV), α-ketoisocaproic acid (KIC), and α-keto-β-methylvaleric acid (KMV)) are related to many diseases such as myeloid leukemia, liver cancer, and diabetes mellitus. A rapid quantitative analytical method for BCKAs using pillar array columns was developed. α-Keto acids were labeled with 1,2-diamino-4,5-methylenedioxybenzene (DMB), followed by their separation on octadecylsilane-treated pillar array columns with MeOH/H2O as the mobile phase. Five DMB-labelled α-keto acids including the internal standard were separated in 160 s. The lower limits of quantification for DMB-α-keto acids were 2-5 μM. The intra- and interday precisions were 2.9-6.6 % and 5.2-10.7 %, respectively. The developed method was applied to BCKA quantification in human plasma samples; KIV, KIC, and KMV concentrations were determined to be 13.8, 24.2, and 15.2 μM, respectively. The method realized rapid, sensitive, and precise analysis of BCKAs and can be applied for clinical diagnosis.
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Affiliation(s)
- Takuya Fujiwara
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 1130033, Japan
| | - Takashi Funatsu
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 1130033, Japan
| | - Makoto Tsunoda
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 1130033, Japan.
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10
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Mielczarek P, Silberring J, Smoluch M. MINIATURIZATION IN MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2020; 39:453-470. [PMID: 31793697 DOI: 10.1002/mas.21614] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
Expectations for continuous miniaturization in mass spectrometry are not declining for years. Portable instruments are highly welcome by the industry, science, space agencies, forensic laboratories, and many other units. All are striving for the small, cheap, and as good as possible instruments. This review describes the recent developments of miniature mass spectrometers and also provides selected applications where these devices are used. Upcoming perspectives of further development are also discussed. @ 2019 John Wiley & Sons Ltd. Mass Spec Rev.
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Affiliation(s)
- Przemyslaw Mielczarek
- Department of Biochemistry and Neurobiology, Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Mickiewicza 30, 30-059, Krakow, Poland
- Laboratory of Proteomics and Mass Spectrometry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343, Krakow, Poland
| | - Jerzy Silberring
- Department of Biochemistry and Neurobiology, Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Mickiewicza 30, 30-059, Krakow, Poland
- Centre of Polymer and Carbon Materials, Polish Academy of Sciences, Curie-Sklodowskiej St. 34, 41-819, Zabrze, Poland
| | - Marek Smoluch
- Department of Biochemistry and Neurobiology, Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Mickiewicza 30, 30-059, Krakow, Poland
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11
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The checkerboard model for the Eddy-dispersion in Laminar flows through porous media. Part II: Application to ordered and disordered 2-D flow systems. J Chromatogr A 2020; 1624:461196. [DOI: 10.1016/j.chroma.2020.461196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 11/24/2022]
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12
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Blumberg LM. Kinetic performance factor – a proportional metric for comparing performance of differently structured liguid chromatography columns. J Chromatogr A 2020; 1623:461101. [DOI: 10.1016/j.chroma.2020.461101] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 01/24/2023]
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13
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Kourmpetis I, Kastania AS, Ellinas K, Tsougeni K, Baca M, De Malsche W, Gogolides E. Gradient-temperature hot-embossing for dense micropillar array fabrication on thick cyclo-olefin polymeric plates: An example of a microfluidic chromatography column fabrication. MICRO AND NANO ENGINEERING 2019. [DOI: 10.1016/j.mne.2019.100042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Salmean C, Dimartino S. 3D-Printed Stationary Phases with Ordered Morphology: State of the Art and Future Development in Liquid Chromatography. Chromatographia 2018. [DOI: 10.1007/s10337-018-3671-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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15
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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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16
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Haghighi F, Talebpour Z, Nezhad AS. Towards fully integrated liquid chromatography on a chip: Evolution and evaluation. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.05.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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17
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Affiliation(s)
- Xilong Yuan
- Department of Chemistry, Queen's University , Kingston, Ontario K7L 3N6, Canada
| | - Richard D Oleschuk
- Department of Chemistry, Queen's University , Kingston, Ontario K7L 3N6, Canada
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18
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Nawada S, Dimartino S, Fee C. Dispersion behavior of 3D-printed columns with homogeneous microstructures comprising differing element shapes. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2017.02.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Smirnova A, Shimizu H, Pihosh Y, Mawatari K, Kitamori T. On-Chip Step-Mixing in a T-Nanomixer for Liquid Chromatography in Extended-Nanochannels. Anal Chem 2016; 88:10059-10064. [DOI: 10.1021/acs.analchem.6b02395] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adelina Smirnova
- Graduate School of Engineering,
Applied Chemistry Department, The University of Tokyo, Tokyo, 113-8656 Japan
| | - Hisashi Shimizu
- Graduate School of Engineering,
Applied Chemistry Department, The University of Tokyo, Tokyo, 113-8656 Japan
| | - Yuriy Pihosh
- Graduate School of Engineering,
Applied Chemistry Department, The University of Tokyo, Tokyo, 113-8656 Japan
| | - Kazuma Mawatari
- Graduate School of Engineering,
Applied Chemistry Department, The University of Tokyo, Tokyo, 113-8656 Japan
| | - Takehiko Kitamori
- Graduate School of Engineering,
Applied Chemistry Department, The University of Tokyo, Tokyo, 113-8656 Japan
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20
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Lincoln DR, Lavrik NV, Kravchenko II, Sepaniak MJ. Retention in Porous Layer Pillar Array Planar Separation Platforms. Anal Chem 2016; 88:8741-8. [PMID: 27510171 DOI: 10.1021/acs.analchem.6b02079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work presents the retention capabilities and surface area enhancement of highly ordered, high-aspect-ratio, open-platform, two-dimensional (2D) pillar arrays when coated with a thin layer of porous silicon oxide (PSO). Photolithographically prepared pillar arrays were coated with 50-250 nm of PSO via plasma-enhanced chemical vapor deposition and then functionalized with either octadecyltrichlorosilane or n-butyldimethylchlorosilane. Theoretical calculations indicate that a 50 nm layer of PSO increases the surface area of a pillar nearly 120-fold. Retention capabilities were tested by observing capillary-action-driven development under various conditions, as well as by running one-dimensional separations on varying thicknesses of PSO. Increasing the thickness of PSO on an array clearly resulted in greater retention of the analyte(s) in question in both experiments. In culmination, a two-dimensional separation of fluorescently derivatized amines was performed to further demonstrate the capabilities of these fabricated platforms.
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Affiliation(s)
- Danielle R Lincoln
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Nickolay V Lavrik
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States
| | - Ivan I Kravchenko
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States
| | - Michael J Sepaniak
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
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21
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Yan X, Wang Q, Li N. Predictive model of solute transport with reversible adsorption in spatially periodic hierarchical porous media. J Chromatogr A 2015; 1407:69-75. [PMID: 26145453 DOI: 10.1016/j.chroma.2015.06.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/08/2015] [Accepted: 06/09/2015] [Indexed: 10/23/2022]
Abstract
Solute transport in hierarchical porous media with reversible adsorption is predicted by the volume averaging method. A transient macroscopic advection-diffusion equation is derived to describe the multiscale solute transport problem. The theoretical expression of the dispersion tensor is obtained which is the function of pore-scale velocity profile. Steady closure equations are derived to calculate the dispersion tensor. With the aid of pore-scale simulation in unit cells of the hierarchical porous media, the dispersion tensor can be calculated. The model is verified by comparing its predictions and obtaining favorable agreement with results of direct numerical simulations and with experimental data for columns comprised of ordered, porous pillars. It is straightforward to use the model to predict the solute transport behavior in fixed beds packed with particles.
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Affiliation(s)
- Xiaohong Yan
- Department of Chemical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
| | - Qiuwang Wang
- Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Nan Li
- Xi'an Haitang Vocational College, Xi'an, Shaanxi, 710049, China
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22
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Kirchner TB, Hatab NA, Lavrik NV, Sepaniak MJ. Highly ordered silicon pillar arrays as platforms for planar chromatography. Anal Chem 2013; 85:11802-8. [PMID: 24228860 DOI: 10.1021/ac402261p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Unlike HPLC, there has been sparse advancement in the stationary phases used for planar chromatography. Nevertheless, modernization of planar chromatography platforms can further highlight the technique's ability to separate multiple samples simultaneously, utilize orthogonal separation formats, image (detect) separations without rigorous temporal demands, and its overall simplicity. This paper describes the fabrication and evaluation of ordered pillar arrays that are chemically modified for planar chromatography and inspected by fluorescence microscopy to detect solvent development and analyte bands (spots). Photolithography, in combination with anisotropic deep reactive ion etching, is used to produce uniform high aspect ratio silicon pillars. The pillar heights, diameters, and pitch variations are approximately 15-20 μm, 1-3 μm, and 2-6 μm, respectively, with the total pillar array size typically 1 cm × 3 cm. The arrays are imaged using scanning electron microscopy in order to measure the pillar diameter and pitch as well as analyze the pillar sidewalls after etching and stationary phase functionalization. These fluidic arrays will enable exploration of the impact on mass transport and chromatographic efficiency caused by altering the pillar array morphology. A C18 reverse stationary phase (RP), common RP solvents that are transported by traditional but uniquely rapid capillary flow, and Rhodamine 6G (R6G) as the preliminary analyte are used for this initial evaluation. The research presented in this article is aimed at understanding and overcoming the unique challenges in developing and utilizing ordered pillar arrays as a new platform for planar chromatography: focusing on fabrication of expansive arrays, studies of solvent transport, methods to create compatible sample spots, and an initial evaluation of band dispersion.
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Affiliation(s)
- Teresa B Kirchner
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
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Op De Beeck J, Callewaert M, Ottevaere H, Gardeniers H, Desmet G, De Malsche W. On the Advantages of Radially Elongated Structures in Microchip-Based Liquid Chromatography. Anal Chem 2013; 85:5207-12. [DOI: 10.1021/ac400576s] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
| | | | | | - Han Gardeniers
- Mesoscale Chemical Systems, Mesa+ Institute for Nanotechnology, P.O. Box 217, 7500AE
Enschede, The Netherlands
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Affiliation(s)
- Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels,
Belgium
| | - Sebastiaan Eeltink
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels,
Belgium
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25
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Sukas S, De Malsche W, Desmet G, Gardeniers HJGE. Performance evaluation of different design alternatives for microfabricated nonporous fused silica pillar columns for capillary electrochromatography. Anal Chem 2012; 84:9996-10004. [PMID: 23106365 DOI: 10.1021/ac302450z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An experimental study comparing the performance of different designs for microfabricated column structures for microchip capillary electrochromatography is presented. The work is a follow-up to our previously published modeling and simulation study on the same topic. Experiments were performed using fused silica microchips with and without octadecyltrimethoxysilane coating for nonretained and retained modes of operation, respectively. Showing the same trends as the modeling results, the foil shape produces a significant decrease in plate height with an increase of around 15% in mobile phase velocity in nonretained measurements of Coumarin 480 (C480). Measured plate heights at 1 kV/cm applied electric field were 0.77, 1.33, and 1.42 μm for foil, diamond, and hexagon, respectively. Chromatographic runs of C480 yielded minimal plate height values of 1.85 and 3.28 μm for foil and diamond, respectively. The optimization of the shape and placement of the structures appeared to have a considerable impact on the achievable performance.
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Affiliation(s)
- Sertan Sukas
- Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands
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26
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Li Y, Aggarwal P, Tolley H, Lee M. Organic Monolith Column Technology for Capillary Liquid Chromatography. ADVANCES IN CHROMATOGRAPHY 2012; 50:237-80. [DOI: 10.1201/b11636-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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27
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Aggarwal P, Tolley HD, Lee ML. Monolithic bed structure for capillary liquid chromatography. J Chromatogr A 2012; 1219:1-14. [DOI: 10.1016/j.chroma.2011.10.083] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 10/25/2011] [Indexed: 10/15/2022]
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28
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Taylor LC, Kirchner TB, Lavrik NV, Sepaniak MJ. Surface enhanced Raman spectroscopy for microfluidic pillar arrayed separation chips. Analyst 2012; 137:1005-12. [DOI: 10.1039/c2an16239c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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29
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Lavrik N, Taylor L, Sepaniak M. Nanotechnology and chip level systems for pressure driven liquid chromatography and emerging analytical separation techniques: A review. Anal Chim Acta 2011; 694:6-20. [DOI: 10.1016/j.aca.2011.03.059] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 03/25/2011] [Accepted: 03/29/2011] [Indexed: 01/13/2023]
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30
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Barrow DA, Castell OK, Sykes N, Myers P, Ritchie H. A microfabricated graphitic carbon column for high performance liquid chromatography. J Chromatogr A 2010; 1218:1983-7. [PMID: 21241990 DOI: 10.1016/j.chroma.2010.11.086] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 11/23/2010] [Accepted: 11/29/2010] [Indexed: 11/18/2022]
Abstract
We report the first development of a novel, planar, microfluidic, graphitic carbon separations column utilizing an array of graphitic micropillars of diamond cross-section as the chromatographic stationary phase. 795 nm femtosecond laser ablation was employed to subtractively machine fluidic architectures and a micropillared array in a planar, graphitic substrate as a monolithic structure. A sample injector was integrated on-chip, together with fluid-flow distribution architectures to minimize band-broadening and ensure sample equi-distribution across the micro-pillared column width. The separations chip was interfaced directly to the ESI probe of a Thermofisher Surveyor mass spectrometer, enabling the detection of test-mixture analytes following their differential retention on the micro-pillared graphitic column, thus demonstrating the exciting potential of this novel separations format. Importantly, unlike porous, graphitic microspheres, the temperature and pressure resilience of the microfluidic device potentially enables use in subcritical H(2)O chromatography.
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Affiliation(s)
- D A Barrow
- Cardiff School of Engineering, Cardiff University, 1-5 The Parade, Cardiff CF24 3AA, UK.
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31
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Illa X, De Malsche W, Gardeniers H, Desmet G, Romano-Rodríguez A. Experimental study of the retention properties of a cyclo olefin polymer pillar array column in reversed-phase mode. J Sep Sci 2010; 33:3313-8. [DOI: 10.1002/jssc.201000360] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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32
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Taylor LC, Lavrik NV, Sepaniak MJ. High-aspect-ratio, silicon oxide-enclosed pillar structures in microfluidic liquid chromatography. Anal Chem 2010; 82:9549-56. [PMID: 21028836 DOI: 10.1021/ac1023342] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The present paper discusses the ability to separate chemical species using high-aspect-ratio, silicon oxide-enclosed pillar arrays. These miniaturized chromatographic systems require smaller sample volumes, experience less flow resistance, and generate superior separation efficiency over traditional packed bed liquid chromatographic columns, improvements controlled by the increased order and decreased pore size of the systems. In our distinctive fabrication sequence, plasma-enhanced chemical vapor deposition (PECVD) of silicon oxide is used to alter the surface and structural properties of the pillars for facile surface modification while improving the pillar mechanical stability and increasing surface area. The separation behavior of model compounds within our pillar systems indicated an unexpected hydrophobic-like separation mechanism. The effects of organic modifier, ionic concentration, and pressure-driven flow rate were studied. A decrease in the organic content of the mobile phase increased peak resolution while detrimentally effecting peak shape. A resolution of 4.7 (RSD = 3.7%) was obtained for nearly perfect Gaussian shaped peaks, exhibiting plate heights as low as 1.1 and 1.8 μm for fluorescein and sulforhodamine B, respectively. Contact angle measurements and DART mass spectrometry analysis indicate that our employed elastomeric soft bonding technique modifies pillar properties, creating a fortuitous stationary phase. This discovery provides evidence supporting the ability to easily functionalize PECVD oxide surfaces by gas-phase reactions.
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Affiliation(s)
- Lisa C Taylor
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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33
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De Malsche W, Zhang L, Op De Beeck J, Vangelooven J, Majeed B, Desmet G. Micron-sized pillars for ion-pair reversed-phase DNA separations. J Sep Sci 2010; 33:3613-8. [DOI: 10.1002/jssc.201000538] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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34
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Sukas S, Desmet G, Gardeniers HJGE. Novel shape and placement definitions with retention modeling for solid microfabricated pillar columns for CEC and HPLC. Electrophoresis 2010; 31:3681-90. [DOI: 10.1002/elps.201000370] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 09/09/2010] [Accepted: 09/09/2010] [Indexed: 11/11/2022]
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35
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Illa X, De Malsche W, Gardeniers H, Desmet G, Romano-Rodríguez A. Experimental study of the depth influence on the band broadening effect in a cyclo-olefin polymer column containing an array of ordered pillars. J Chromatogr A 2010; 1217:5817-21. [DOI: 10.1016/j.chroma.2010.07.057] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 06/30/2010] [Accepted: 07/21/2010] [Indexed: 11/30/2022]
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36
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Lavrik NV, Taylor LC, Sepaniak MJ. Enclosed pillar arrays integrated on a fluidic platform for on-chip separations and analysis. LAB ON A CHIP 2010; 10:1086-1094. [PMID: 20358118 DOI: 10.1039/b920275g] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Due to the difficulty of reliably producing sealed 3-D structures, few researchers have tackled the challenges of creating pillar beds suitable for miniaturized liquid phase separation systems. Herein, we describe an original processing sequence for the fabrication of enclosed pillar arrays integrated on a fluidic chip which, we believe, will further stimulate interest in this field. Our approach yields a mechanically robust enclosed pillar system that withstands mechanical impacts commonly incurred during processing, sealing and operation, resulting in a design particularly suitable for the research environment. A combination of a wafer-level fabrication sequence with chip-level elastomer bonding allows for chip reusability, an attractive and cost efficient advancement for research applications. The characteristic features in the implemented highly ordered pillar arrays are scalable to submicron dimensions. The proposed fluidic structures are suitable for handling picolitre sample volumes and offer prospects for substantial improvements in separation efficiency and permeability over traditional packed and monolithic columns. Our experimental observations indicate plate heights as low as 0.76 microm for a 10 mm long pillar bed. Theoretical calculations confirm that ordered pillar arrays with submicron pore sizes combine superior analysis speed, picolitre sample volumes, high permeability and reasonably large plate numbers on a small footprint. In addition, we describe a fluidic interface that provides streamlined coupling of the fabricated structures with off-chip fluidic components.
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Affiliation(s)
- Nickolay V Lavrik
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
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37
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Use of non-porous pillar array columns for the separation of Pseudomonas pyoverdine siderophores as an example of a real-world biological sample. J Chromatogr A 2009; 1216:8603-11. [DOI: 10.1016/j.chroma.2009.10.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 09/29/2009] [Accepted: 10/06/2009] [Indexed: 11/19/2022]
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38
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Detobel F, Eghbali H, De Bruyne S, Terryn H, Gardeniers H, Desmet G. Effect of the presence of an ordered micro-pillar array on the formation of silica monoliths. J Chromatogr A 2009; 1216:7360-7. [DOI: 10.1016/j.chroma.2009.03.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 03/04/2009] [Accepted: 03/06/2009] [Indexed: 11/16/2022]
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39
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Wu RG, Yang CS, Wang PC, Tseng FG. Nanostructured pillars based on vertically aligned carbon nanotubes as the stationary phase in micro-CEC. Electrophoresis 2009; 30:2025-31. [DOI: 10.1002/elps.200900113] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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40
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Vangelooven J, Malsche WD, Detobel F, Gardeniers H, Desmet G. High−Speed Shear-Driven Flows Through Microstructured 1D-Nanochannels. Anal Chem 2008; 81:943-52. [DOI: 10.1021/ac801691e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joris Vangelooven
- Department of Chemical Engineering, Vrije Universiteit Brussel, B-1050 Brussels, Belgium, and Research Program Mesofluidics, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
| | - Wim De Malsche
- Department of Chemical Engineering, Vrije Universiteit Brussel, B-1050 Brussels, Belgium, and Research Program Mesofluidics, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
| | - Frederik Detobel
- Department of Chemical Engineering, Vrije Universiteit Brussel, B-1050 Brussels, Belgium, and Research Program Mesofluidics, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
| | - Han Gardeniers
- Department of Chemical Engineering, Vrije Universiteit Brussel, B-1050 Brussels, Belgium, and Research Program Mesofluidics, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, B-1050 Brussels, Belgium, and Research Program Mesofluidics, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
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41
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Eghbali H, Verdoold V, Vankeerberghen L, Gardeniers H, Desmet G. Experimental Investigation of the Band Broadening Arising from Short-Range Interchannel Heterogeneities in Chromatographic Beds under the Condition of Identical External Porosity. Anal Chem 2008; 81:705-15. [DOI: 10.1021/ac802124p] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Hamed Eghbali
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium, Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
| | - Vincent Verdoold
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium, Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
| | - Lieselot Vankeerberghen
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium, Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
| | - Han Gardeniers
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium, Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium, Mesoscale Chemical Systems, MESA+ Institute for Nanotechnology, Enschede, The Netherlands
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42
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Gustafsson O, Mogensen KB, Kutter JP. Underivatized cyclic olefin copolymer as substrate material and stationary phase for capillary and microchip electrochromatography. Electrophoresis 2008; 29:3145-52. [DOI: 10.1002/elps.200800131] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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43
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Dauriac V, Descroix S, Chen Y, Peltre G, Sénéchal H. Isoelectric focusing in an ordered micropillar array. Electrophoresis 2008; 29:2945-52. [DOI: 10.1002/elps.200800052] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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44
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Malsche WD, Gardeniers H, Desmet G. Experimental Study of Porous Silicon Shell Pillars under Retentive Conditions. Anal Chem 2008; 80:5391-400. [DOI: 10.1021/ac800424q] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wim De Malsche
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium, and Research Programme Mesofluidics, MESA+ Institute for Nanotechnology, MESA+ Research Institute, Enschede, The Netherlands
| | - Han Gardeniers
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium, and Research Programme Mesofluidics, MESA+ Institute for Nanotechnology, MESA+ Research Institute, Enschede, The Netherlands
| | - Gert Desmet
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium, and Research Programme Mesofluidics, MESA+ Institute for Nanotechnology, MESA+ Research Institute, Enschede, The Netherlands
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45
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Particle packed columns and monolithic columns in high-performance liquid chromatography-comparison and critical appraisal. J Chromatogr A 2008; 1184:393-415. [DOI: 10.1016/j.chroma.2007.11.118] [Citation(s) in RCA: 271] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 11/28/2007] [Accepted: 11/30/2007] [Indexed: 11/29/2022]
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46
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Topographic structures and chromatographic supports in microfluidic separation devices. J Chromatogr A 2008; 1184:560-72. [DOI: 10.1016/j.chroma.2007.09.086] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 09/24/2007] [Accepted: 09/27/2007] [Indexed: 01/16/2023]
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47
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De Malsche W, Clicq D, Verdoold V, Gzil P, Desmet G, Gardeniers H. Integration of porous layers in ordered pillar arrays for liquid chromatography. LAB ON A CHIP 2007; 7:1705-1711. [PMID: 18030390 DOI: 10.1039/b710507j] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The present paper describes a method for the production of partly porous micro-pillars in columns suitable for use in liquid chromatography. These layers increase the available surface at least two orders of magnitude without destroying the huge benefits of the ordered nature of the system. A process flow was developed that enabled us to create a 550 nm thick porous layer on the pillar array in a sealed channel configuration, withstanding pressures up to at least 70 bar. Measuring band broadening under non-retained conditions, only a modest increase in plate height was observed in the porous pillar array as compared to that in a non-porous pillar array. The homogeneity of the layers was demonstrated using an optical microscope and SEM pictures and by monitoring peak velocities at constant pressures. The internal porosity was determined using particles with a diameter larger than the mesopores in combination with a dye that could penetrate into the pores.
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Affiliation(s)
- Wim De Malsche
- Vrije Universiteit Brussel, Department of Chemical Engineering, Brussels, Belgium.
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48
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Eghbali H, De Malsche W, De Smet J, Billen J, De Pra M, Kok WT, Schoenmakers PJ, Gardeniers H, Desmet G. Experimental investigation of the band broadening originating from the top and bottom walls in micromachined nonporous pillar array columns. J Sep Sci 2007; 30:2605-13. [PMID: 17893848 DOI: 10.1002/jssc.200700203] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We report on the experimental investigation of the effect of the top and bottom wall plates in micromachined nonporous pillar array columns. It has been found that their presence yields an additional c-term type of band broadening that can make up a significant fraction of the total band broadening (at least if considering nonporous pillars and a nonretained tracer). Their presence also induces a clear (downward) shift of the optimal velocity. These observations are, however in excellent quantitative agreement with the theoretical expectations obtained from a computational fluid dynamics study. The presently obtained experimental results, hence, demonstrate that the employed high aspect ratio Bosch etching process can be used to fabricate micromachined pillar arrays that are sufficiently refined to achieve the theoretical performance limit.
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Affiliation(s)
- Hamed Eghbali
- Department of Chemical Engineering, Vrije Universiteit Brussel, Brussel, Belgium
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49
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Broeckhoven K, Desmet G. Approximate transient and long time limit solutions for the band broadening induced by the thin sidewall-layer in liquid chromatography columns. J Chromatogr A 2007; 1172:25-39. [DOI: 10.1016/j.chroma.2007.09.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 09/20/2007] [Accepted: 09/21/2007] [Indexed: 10/22/2022]
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50
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Billen J, Desmet G. Understanding and design of existing and future chromatographic support formats. J Chromatogr A 2007; 1168:73-99; discussion 71-2. [PMID: 17706659 DOI: 10.1016/j.chroma.2007.07.069] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 07/24/2007] [Accepted: 07/27/2007] [Indexed: 11/26/2022]
Abstract
The present contribution reviews the use of alternative support formats as a means to surpass the chromatographic performance of the packed bed of spheres. First, a number of idealized structures are considered to obtain a general insight in how the performance of a chromatographic support depends on its shape and size, using the isocratic peak-capacity generation speed as the main performance indicator. Using this criterion, it is found that the packing density or, equivalently, the external porosity, is the most important of all geometrical shape factors. Depending on whether the sample consists of weakly or strongly retained components, the optimal external porosity can be expected to vary between 60% and a value near 100%. The optimal exploitation of a high external porosity, however, also requires overall shrinkage of the domain size, towards and into the sub-micron range. With the current fabrication technologies, this requirement seems difficult to achieve. In the presence of a lower limit on the characteristic support size, each range of desired plate numbers or peak capacities has its own optimal external porosity, ranging from a very low value (high packing density) for high speed, small peak capacity applications, to very high external porosities (low packing density) for applications requiring a very large peak capacity. Subsequently, the obtained theoretical insights are used to review and discuss the past and current research on alternative support formats. Finally, a number of emerging micro- and nano-fabrication technologies are introduced and their potential for the future production of supports with improved shape and homogeneity is discussed.
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Affiliation(s)
- J Billen
- Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
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