1
|
Hajba L, Guttman A. Recent Advances in Capillary Electrochromatography of Proteins and Carbohydrates in the Biopharmaceutical and Biomedical Field. Crit Rev Anal Chem 2020; 51:289-298. [PMID: 32022586 DOI: 10.1080/10408347.2020.1720589] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Capillary electrochromatography (CEC) is a powerful hybrid separation technique that combines capillary electrophoresis and capillary chromatography, capable to address the analytical challenges of proteomics and glycomics. The focus of this paper is to review the recent developments in capillary electrochromatography of proteins and carbohydrates. The different column types applied in capillary electrochromatography such as packed bed, open tubular and monoliths are conferred in detail with respective separation examples. A comprehensive comparison is also given listing the mostly utilized coating methods, stationary phase materials and column preparation methods. The choice of porogenic solvent combinations for monolithic column fabrication is thoroughly discussed, paying close attention to the fine tuning options for the separation driving electroosmotic flow. Application examples of CEC in process analytical technology for the biopharmaceutical and biomarker discovery in the biomedical fields are also given.
Collapse
Affiliation(s)
- L Hajba
- Translational Glycomics Research Group, Research Institute of Biomolecular and Chemical Engineering, University of Pannonia, Veszprem, Hungary
| | - A Guttman
- Translational Glycomics Research Group, Research Institute of Biomolecular and Chemical Engineering, University of Pannonia, Veszprem, Hungary.,Horváth Csaba Memorial Laboratory for Bioseparation Sciences, Research Center for Molecular Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| |
Collapse
|
2
|
Wang H, Ou J, Bai J, Liu Z, Yao Y, Chen L, Peng X, Zou H. Improving permeability and chromatographic performance of poly(pentaerythritol diacrylate monostearate) monolithic column via photo-induced thiol-acrylate polymerization. J Chromatogr A 2016; 1436:100-8. [DOI: 10.1016/j.chroma.2016.01.063] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/18/2016] [Accepted: 01/23/2016] [Indexed: 10/22/2022]
|
3
|
Jiao X, Shen S, Shi T. One-pot preparation of a novel monolith for high performance liquid chromatography applications. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 1007:100-9. [DOI: 10.1016/j.jchromb.2015.10.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/18/2015] [Accepted: 10/20/2015] [Indexed: 11/28/2022]
|
4
|
Lin Z, Wang J, Yin X, Tan X, Yu R, Zheng J, Zhang L, Chen G. Polymer monolithic capillary column fabricated by using monodisperse iron oxide nanocrystal template to enhance the electrochromatographic separation of small molecules. Electrophoresis 2014; 35:1947-55. [DOI: 10.1002/elps.201300647] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 02/17/2014] [Accepted: 03/16/2014] [Indexed: 11/10/2022]
Affiliation(s)
- Zian Lin
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety; College of Chemistry, Fuzhou University; Fuzhou Fujian P. R. China
| | - Juan Wang
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety; College of Chemistry, Fuzhou University; Fuzhou Fujian P. R. China
| | - Xiaofei Yin
- The First Institute of Oceanography; SOA Qingdao P. R. China
| | - Xiaoqing Tan
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety; College of Chemistry, Fuzhou University; Fuzhou Fujian P. R. China
| | - Ruifang Yu
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety; College of Chemistry, Fuzhou University; Fuzhou Fujian P. R. China
| | - Jiangnan Zheng
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety; College of Chemistry, Fuzhou University; Fuzhou Fujian P. R. China
| | - Lan Zhang
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety; College of Chemistry, Fuzhou University; Fuzhou Fujian P. R. China
| | - Guonan Chen
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety; College of Chemistry, Fuzhou University; Fuzhou Fujian P. R. China
| |
Collapse
|
5
|
Zhong J, Hao M, Li R, Bai L, Yang G. Preparation and characterization of poly(triallyl isocyanurate -co- trimethylolpropane triacrylate) monolith and its applications in the separation of small molecules by liquid chromatography. J Chromatogr A 2014; 1333:79-86. [DOI: 10.1016/j.chroma.2014.01.072] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/27/2014] [Accepted: 01/27/2014] [Indexed: 11/26/2022]
|
6
|
Gökaltun A, Aydoğan C, Çelebi B, Denizli A, Tuncel A. Preparation of an Electrochromatographic Stationary Phase Using a New Polymethacrylate Monolith with Chloropropyl Functionality. Chromatographia 2014. [DOI: 10.1007/s10337-013-2620-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
7
|
Capillary Electrophoresis and Capillary Electrochromatography. CHROMATOGRAPHY 2013. [DOI: 10.1002/9780471980582.ch13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
8
|
Aguiar VS, Bottoli CBG. Development and characterization of hydrophobic organic monolithic columns for use in capillary electrochromatography. Microchem J 2013. [DOI: 10.1016/j.microc.2012.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
9
|
Lin Z, Huang H, Li S, Wang J, Tan X, Zhang L, Chen G. Preparation of phenylboronic acid-silica hybrid monolithic column with one-pot approach for capillary liquid chromatography of biomolecules. J Chromatogr A 2013; 1271:115-23. [DOI: 10.1016/j.chroma.2012.11.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/09/2012] [Accepted: 11/15/2012] [Indexed: 02/09/2023]
|
10
|
Huang H, Lin Z, Lin Y, Sun X, Xie Y, Zhang L, Chen G. Preparation and evaluation of poly(4-vinylphenylboronic acid-co-pentaerythritol triacrylate) monolithic column for capillary liquid chromatography of small molecules and proteins. J Chromatogr A 2012; 1251:82-90. [DOI: 10.1016/j.chroma.2012.06.032] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/09/2012] [Accepted: 06/11/2012] [Indexed: 11/28/2022]
|
11
|
Karenga S, El Rassi Z. Controlling retention, selectivity and magnitude of EOF by segmented monolithic columns consisting of octadecyl and naphthyl monolithic segments--applications to RP-CEC of both neutral and charged solutes. Electrophoresis 2011; 32:1033-43. [PMID: 21455910 DOI: 10.1002/elps.201000563] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 11/22/2010] [Accepted: 11/30/2010] [Indexed: 11/12/2022]
Abstract
Monolithic capillaries made of two adjoining segments each filled with a different monolith were introduced for the control and manipulation of the electroosmotic flow (EOF), retention and selectivity in reversed phase-capillary electrochromatography (RP-CEC). These columns were called segmented monolithic columns (SMCs) where one segment was filled with a naphthyl methacrylate monolith (NMM) to provide hydrophobic and π-interactions, while the other segment was filled with an octadecyl acrylate monolith (ODM) to provide solely hydrophobic interaction. The ODM segment not only provided hydrophobic interactions but also functioned as the EOF accelerator segment. The average EOF of the SMC increased linearly with increasing the fractional length of the ODM segment. The neutral SMC provided a convenient way for tuning EOF, selectivity and retention in the absence of annoying electrostatic interactions and irreversible solute adsorption. The SMCs allowed the separation of a wide range of neutral solutes including polycyclic aromatic hydrocarbons (PAHs) that are difficult to separate using conventional alkyl-bonded stationary phases. In all cases, the k' of a given solute was a linear function of the fractional length of the ODM or NMM segment in the SMCs, thus facilitating the tailoring of a given SMC to solve a given separation problem. At some ODM fractional length, the fabricated SMC allowed the separation of charged solutes such as peptides and proteins that could not otherwise be achieved on a monolithic column made from NMM as an isotropic stationary phase due to the lower EOF exhibited by this monolith.
Collapse
Affiliation(s)
- Samuel Karenga
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74075, USA
| | | |
Collapse
|
12
|
Kadi A, Hefnawy M, Al-Majed A, Alonezi S, Asiri Y, Attia S, Abourashed E, El-Subbagh H. Liquid chromatographic high-throughput analysis of the new ultra-short acting hypnotic ‘HIE-124’ and its metabolite in mice serum using a monolithic silica column. Analyst 2011; 136:591-7. [DOI: 10.1039/c0an00381f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
13
|
Karenga S, El Rassi Z. Trends in nonpolar polymer-based monolithic columns for reversed-phase capillary electrochromatography. Electrophoresis 2010; 32:90-104. [PMID: 21171116 DOI: 10.1002/elps.201000490] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 09/30/2010] [Accepted: 10/05/2010] [Indexed: 11/11/2022]
Abstract
This review article is concerned with describing the various strategies that have been introduced for the preparation of nonpolar polymer-based monolithic columns for RP-CEC. First, the various traditional ways of generating the EOF that involved the introduction of fixed charges on the surface of the monoliths are reviewed. This is followed by a description of the development of neutral monoliths as the most promising monoliths for the separation of a wide range of neutral and charged species at a relatively moderate to strong EOF in the absence of electrostatic attraction or repulsion.
Collapse
Affiliation(s)
- Samuel Karenga
- Department of Chemistry, Oklahoma State University, Stillwater, OK, USA
| | | |
Collapse
|
14
|
Lu M, Feng Q, Lu Q, Cai Z, Zhang L, Chen G. Preparation and evaluation of the highly cross-linked poly(1-hexadecane-co-trimethylolpropane trimethacrylate) monolithic column for capillary electrochromatography. Electrophoresis 2009; 30:3540-7. [DOI: 10.1002/elps.200900018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
15
|
Svec F. CEC: selected developments that caught my eye since the year 2000. Electrophoresis 2009; 30 Suppl 1:S68-82. [PMID: 19517503 DOI: 10.1002/elps.200900062] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
During the last decade, a number of new developments have emerged in the field of CEC. This paper focuses only on monolithic columns prepared from synthetic polymers. Monolithic columns have become a well-established format of stationary phases for CEC immediately after their inception in the mid-1990s. They are readily prepared in situ from liquid precursors. Also, the control over both porous properties and surface chemistries is easy to achieve. These advantages make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials. Since the number of papers concerned with just this single topic of polymer-based monolithic CEC columns is large, this overview describes only those approaches this author found interesting.
Collapse
Affiliation(s)
- Frantisek Svec
- The Molecular Foundry, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8197, USA.
| |
Collapse
|
16
|
Polymeric strong cation-exchange monolithic column for capillary liquid chromatography of peptides and proteins. J Sep Sci 2009; 32:2565-73. [DOI: 10.1002/jssc.200900255] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
17
|
|
18
|
CHOODUM A, THAVARUNGKUL P, KANATHARANA P, SMITH NW. Ecstasy Analysis by Monolithic Materials-Capillary Electrochromatography. ANAL SCI 2009; 25:517-22. [DOI: 10.2116/analsci.25.517] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Aree CHOODUM
- Trace Analysis and Biosensor Research Center, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University
| | - Panote THAVARUNGKUL
- Trace Analysis and Biosensor Research Center, Department of Physics, Faculty of Science, Prince of Songkla University
| | - Proespichaya KANATHARANA
- Trace Analysis and Biosensor Research Center, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University
| | - Norman W. SMITH
- Micro Separations Group, Pharmaceutical Science Research Division, King's College, London
| |
Collapse
|
19
|
Preparation of a mixed-mode hydrophilic interaction/anion-exchange polymeric monolithic stationary phase for capillary liquid chromatography of polar analytes. J Chromatogr A 2008; 1216:801-6. [PMID: 19108844 DOI: 10.1016/j.chroma.2008.11.099] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Revised: 11/23/2008] [Accepted: 11/26/2008] [Indexed: 11/23/2022]
Abstract
A novel cationic hydrophilic interaction monolithic stationary phase based on the copolymerization of 2-(methacryloyloxy)ethyltrimethylammonium methyl sulfate (META) and pentaerythritol triacrylate (PETA) in a binary porogenic solvent consisting of cyclohexanol/ethylene glycol was designed for performing capillary liquid chromatography. While META functioned as both the ion-exchange sites and polar ligand provider, the PETA, a trivinyl monomer, was introduced as cross-linker. The monolithic stationary phases with different properties were easily prepared by adjusting the amount of META in the polymerization solution as well as the composition of the porogenic solvent. The hydrophilicity of the monolith increased with increasing content of META in the polymerization mixture. A typical hydrophilic interaction chromatography mechanism was observed when the content of acetonitrile in the mobile phase was higher than 20%. The poly(META-co-PETA) monolith showed very good selectivity for neutral, basic and acidic polar analytes. For polar-charged analytes, both hydrophilic interaction and electrostatic interaction contributed to their retention. Peak tailing of basic compounds was avoided and the efficient separation of benzoic acid derivatives was obtained.
Collapse
|
20
|
Jiang Z, Smith NW, Ferguson PD, Taylor MR. Mixed-mode reversed-phase and ion-exchange monolithic columns for micro-HPLC. J Sep Sci 2008; 31:2774-83. [PMID: 18666170 DOI: 10.1002/jssc.200800124] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This paper describes the fabrication of RP/ion-exchange mixed-mode monolithic materials for capillary LC. Following deactivation of the capillary surface with 3-(trimethoxysilyl)propyl methacrylate (gamma-MAPS), monoliths were formed by copolymerisation of pentaerythritol diacrylate monostearate (PEDAS), 2-sulphoethyl methacrylate (SEMA) with/without ethylene glycol dimethacrylate (EDMA) within 100 microm id capillaries. In order to investigate the porous properties of the monoliths prepared in our laboratory, mercury intrusion porosimetry, SEM and micro-HPLC were used to measure the monolithic structures. The monolithic columns prepared without EDMA showed bad mechanical stability at high pressure, which is undesirable for micro-HPLC applications. However, it was observed that the small amount (5% w/w) of EDMA clearly improved the mechanical stability of the monoliths. In order to evaluate their application for micro-HPLC, a range of neutral, acidic and basic compounds was separated with these capillaries and satisfactory separations were obtained. In order to further investigate the separation mechanism of these monolithic columns, comparative studies were carried out on the poly(PEDAS-co-SEMA) monolithic column and two other monoliths, poly(PEDAS) and poly(PEDAS-co-2-(methacryloyloxy)ethyl-trimethylammonium methylsulphate (METAM)). As expected, different selectivities were observed for the separation of basic compounds on all three monolithic columns using the same separation conditions. The mobile phase pH also showed clear influence on the retention time of basic compounds. This could be explained by ion-exchange interaction between positively charged analytes and the negatively charged sulphate group.
Collapse
Affiliation(s)
- Zhengjin Jiang
- Pharmaceutical Sciences Research Division, King's College London, London, UK
| | | | | | | |
Collapse
|
21
|
Karenga S, El Rassi Z. Neutral octadecyl monolith for reversed phase capillary electrochromatography of a wide range of solutes. J Sep Sci 2008; 31:2677-85. [PMID: 18693309 DOI: 10.1002/jssc.200800310] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A neutral octadecyl monolithic (ODM) column for RP capillary electrochromatography (RP-CEC) has been developed. The ODM column was prepared by the in situ polymerization of octadecyl acrylate (ODA) as the monomer and trimethylolpropanetrimethacrylate (TRIM) as the crosslinker, in a ternary porogenic solvent containing cyclohexanol, ethylene glycol, and water. The ODM column exhibited cathodal EOF over a wide range of pH and ACN concentration in the mobile phase despite the fact that it was devoid of any fixed charges. It is believed that the EOF is due to the adsorption of ions from the mobile phase onto the surface of the monolith thus imparting to the neutral ODM column the zeta potential necessary to support the EOF required for mass transport across the monolithic column. Furthermore, the adsorption of mobile phase ions to the neutral monolith modulated solute retention and affected the separation selectivity. The wide applications of the neutral ODM column were demonstrated by its ability to separate a wide range of small and large solutes, both neutral and charged. While the separation of the neutral solutes was based on RP retention mechanism, the charged solutes were separated on the basis of their electrophoretic mobility and hydrophobic interaction with the C18 ligands of the stationary phase. As a typical result, the neutral monolithic column was able to separate peptides quite rapidly with a separation efficiency of nearly 200,000 plates/m, and this efficiency was exploited in tryptic peptide mapping of standard proteins, e. g., lysozyme and cytochrome C, by isocratic elution.
Collapse
Affiliation(s)
- Samuel Karenga
- Department of Chemistry, Oklahoma State University, OK 74075, USA
| | | |
Collapse
|
22
|
Augustin V, Stachowiak T, Svec F, Fréchet JMJ. CEC separation of peptides using a poly(hexyl acrylate-co-1,4-butanediol diacrylate-co-[2-(acryloyloxy)ethyl]trimethyl ammonium chloride) monolithic column. Electrophoresis 2008; 29:3875-86. [PMID: 18850656 PMCID: PMC2786261 DOI: 10.1002/elps.200700883] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A polyacrylate-based monolithic column bearing cationic functionalities and designed for capillary electrochromatography (CEC) has been prepared via photopolymerization of a mixture of hexyl acrylate, butanediol diacrylate, 2-(acryloyloxy) ethyltrimethyl ammonium chloride (monomers), azobisisobutyronitrile (photoinitiator), acetonitrile, phosphate buffer, and ethanol (porogens). The polymerization process was initiated with UV light at 360 nm. The column performance was evaluated via the separations of alkylbenzenes, substituted anilines, basic drugs, peptides, and a protein digest. The separation of complex peptide mixtures was then studied since such separations constitute a promising application of capillary electrochromatography. In particular, the effects of mobile phase composition, including ionic strength of the buffer solution and the percentage of acetonitrile on the retention factor, the column efficiency, and the resolution were determined. The separations were affected by both interaction of the peptides with the stationary phase and their own electrophoretic mobility. Excellent separations with column efficiencies of up to 160 000 plates/m were achieved for both a mixture of ten well-defined peptides and a tryptic digest of cytochrome c. The fractions of eluent containing peptides of the digest separated in the monolithic column were collected and characterized using matrix-assisted laser desorption ionization mass spectrometry.
Collapse
Affiliation(s)
- Violaine Augustin
- College of Chemistry, University of California, Berkeley, CA 94720, USA
| | | | | | | |
Collapse
|
23
|
Chaisuwan P, Nacapricha D, Wilairat P, Jiang Z, Smith NW. Separation of α-, β-, γ-, δ-tocopherols and α-tocopherol acetate on a pentaerythritol diacrylate monostearate-ethylene dimethacrylate monolith by capillary electrochromatography. Electrophoresis 2008; 29:2301-9. [DOI: 10.1002/elps.200700689] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
24
|
Chen TH, Misra TK, Liu CY. Capillary electrochromatographic separation of peptides using a macrocyclic polyamine for molecular recognition. Electrophoresis 2008; 29:1651-7. [DOI: 10.1002/elps.200700560] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
25
|
Höltzel A, Tallarek U. Ionic conductance of nanopores in microscale analysis systems: where microfluidics meets nanofluidics. J Sep Sci 2007; 30:1398-419. [PMID: 17623420 DOI: 10.1002/jssc.200600427] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this tutorial review we illustrate the origin and dependence on various system parameters of the ionic conductance that exists in discrete nanochannels as well as in nanoporous separation and preconcentration units contained as hybrid configurations, membranes, packed beds, or monoliths in microscale liquid phase analysis systems. A particular complexity arises as external electrical fields are superimposed on internal chemical and electrical potential gradients for tailoring molecular transport. It is demonstrated that the variety of geometries in which the microfluidic/nanofluidic interfaces are realized share common, fundamental features of coupled mass and charge transport, but that phenomena behind the key steps in a particular application can be significantly tuned, depending on the morphology of a material. Thus, the understanding of morphology-related transport in internal and external electrical potential gradients is critical to the performance of a device. This addresses a variety of geometries (slits, channels, filters, membranes, random or regular networks of pores, etc.) and applications, e. g., the gating, sensing, preconcentration, and separation in multifunctional miniaturized devices. Inherently coupled mass and charge transport through ion-permselective (charge-selective) microfluidic/nanofluidic interfaces is analyzed with a stepwise-added complexity and discussed with respect to the morphology of the charge-selective spatial domains. Within this scenario, the electrostatics and electrokinetics in microfluidic and nanofluidic channels, as well as the electrohydrodynamics evolving at microfluidic/nanofluidic interfaces, where microfluidics meets nanofluidics, define the platform of central phenomena.
Collapse
Affiliation(s)
- Alexandra Höltzel
- Institut für Verfahrenstechnik, Otto-von-Guericke-Universität, Magdeburg, Germany
| | | |
Collapse
|
26
|
Al-Rimawi F, Pyell U. Investigation of the ion-exchange properties of methacrylate-based mixed-mode monolithic stationary phases employed as stationary phases in capillary electrochromatography. J Chromatogr A 2007; 1160:326-35. [PMID: 17543314 DOI: 10.1016/j.chroma.2007.05.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 04/30/2007] [Accepted: 05/10/2007] [Indexed: 10/23/2022]
Abstract
The potential of methacrylate-based mixed-mode monolithic stationary phases bearing sulfonic acid groups for the separation of positively charged analytes (alkylanilines, amino acids, and peptides) by capillary electrochromatography (CEC) is investigated. The retention mechanism of protonated alkylanilines as positively charged model solutes on these negatively charged mixed-mode stationary phases is investigated by studying the influence of mobile phase and stationary phase parameters on the corrected retention factor which was calculated by taking the electrophoretic mobility of the solutes into consideration. It is shown that both solvophobic and ion-exchange interactions contribute to the retention of these analytes. The dependence of the corrected retention factor on (1) the concentration of the counter ion ammonium and (2) the number of methylene groups in the alkyl chain of the model analytes investigated shows clearly that a one-site model (solvophobic and ion-exchange interactions take place simultaneously at a single type of site) has to be taken to describe the retention behaviour observed. Comparison of the CEC separation of these charged analytes with electrophoretic mobilities determined by open-tubular capillary electrophoresis shows that mainly chromatographic interactions (solvophobic and ion-exchange interactions) are responsible for the selectivity observed in CEC, while the electrophoretic migration of these analytes plays only a minor role.
Collapse
Affiliation(s)
- Fuad Al-Rimawi
- University of Marburg, Department of Chemistry, Hans-Meerwein-Strasse, D-35032 Marburg, Germany
| | | |
Collapse
|
27
|
Abstract
This review summarizes applications of CEC for the analysis of proteins and peptides. This "hybrid" technique is useful for the analysis of a broad spectrum of proteins and peptides and is a complementary approach to liquid chromatographic and capillary electrophoretic analysis. All modes of CEC are described--granular packed columns, monolithic stationary phases as well as open-tubular CEC. Attention is also paid to pressurized CEC and the chip-based platform.
Collapse
Affiliation(s)
- Ivan Miksík
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
| | | |
Collapse
|
28
|
Freitag R, Hilbrig F. Theory and practical understanding of the migration behavior of proteins and peptides in CE and related techniques. Electrophoresis 2007; 28:2125-44. [PMID: 17557365 DOI: 10.1002/elps.200600792] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
CEC is defined as an analytical method, where the analytes are separated on a chromatographic column in the presence of an applied voltage. The separation of charged analytes in CEC is complex, since chromatographic interaction, electroosmosis and electrophoresis contribute to the experimentally observed behavior. The putative contribution of effects such as surface electrodiffusion has been suggested. A sound theoretical treatment incorporating all effects is currently not available. The question of whether the different effects contribute in an independent or an interdependent manner is still under discussion. In this contribution, the state-of-the-art in the theoretical description of the individual contributions as well as models for the retention behavior and in particular possible dimensionless 'retention factors' is discussed, together with the experimental database for the separation of charged analytes, in particular proteins and peptides, by CEC and related techniques.
Collapse
Affiliation(s)
- Ruth Freitag
- Process Biotechnology, University of Bayreuth, Bayreuth, Germany.
| | | |
Collapse
|
29
|
Patton WF, Panchagnula V, Rockney E, Krull IS. Taking a Walk on the Wild Side with Planar Electrochromatography and Thin‐Layer Electrophoresis: Of Peptides, Proteins, and Proteomics. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070600574978] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Wayne F. Patton
- a PerkinElmer Life and Analytical Sciences, Life Sciences Division , Boston, Massachusetts, USA
| | | | - Erin Rockney
- a PerkinElmer Life and Analytical Sciences, Life Sciences Division , Boston, Massachusetts, USA
| | - Ira S. Krull
- b Department of Chemistry and Chemical Biology , Northeastern University , Boston, Massachusetts, USA
| |
Collapse
|
30
|
Jiang Z, Smith NW, Ferguson PD, Taylor MR. Preparation and characterization of long alkyl chain methacrylate-based monolithic column for capillary chromatography. ACTA ACUST UNITED AC 2007; 70:39-45. [PMID: 17049377 DOI: 10.1016/j.jbbm.2006.08.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 08/25/2006] [Accepted: 08/25/2006] [Indexed: 11/17/2022]
Abstract
This paper describes the fabrication of long alkyl chain methacrylate monolithic materials for using as stationary phases in capillary liquid chromatography. Following deactivation of the capillary surface with 3-(trimethoxysilyl)propyl methacrylate (gamma-MAPS), monoliths were formed by co-polymerisation of stearyl methacrylate (SMA) with ethylene glycol dimethacrylate (EDMA) in the presence of the initiator AIBN and a mixture of porogens including iso-amyl alcohol and 1,4-butanediol. The monoliths were prepared in 100 microm i.d. capillaries and the composition of the polymerisation mixtures were optimised in terms of the ratio of SMA/EDMA, the porogen composition and ratio of porogen to monomers. As the porogen weight fraction decreased, the microglobules became smaller and as expected, the total porosity decreased. In order to determine the usability of such materials, the column permeability K was measured by pumping water through the columns at different linear flow rates. Good results were obtained when these capillaries were used to separate mixtures of weak acids, neutral and basic compounds.
Collapse
Affiliation(s)
- Zhengjin Jiang
- Pharmaceutical Sciences Research Division, King's College London, SE1 9NH, UK
| | | | | | | |
Collapse
|
31
|
Hsieh YL, Chen TH, Liu CY. Capillary electrochromatographic separation of proteins on a column coated with titanium dioxide nanoparticles. Electrophoresis 2006; 27:4288-94. [PMID: 17006881 DOI: 10.1002/elps.200500897] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A TiO2 nanoparticle (TiO2 NP)-coated open-tubular column for the capillary electrochromatographic separation of proteins is described. The surface chemistry of the TiO2 NPs on the inner wall of the fused silica was significantly affected by the running buffer. By varying of the phosphate buffer pH, only cathodic EOF was indicated. The results showed that TiO2 NPs are existed as a complexed form with the buffer ligand. Good separation of conalbumin (ConA), apo-transferrin (apoTf), ovalbumin (OVA), and BSA could be achieved with phosphate buffer (40 mM, pH 8.0) and an applied voltage of 15 kV. Five peaks of glycoisoforms of OVA were observed under these conditions. In comparison with the retention behavior of the analytes on the bare fused-silica column, the new column's high resolving power seems to be predominantly derived from the ligand exchange of the analytes with the phosphate adsorbed onto the TiO2 NPs. The method was also used to separate egg-white proteins. Both acidic and basic proteins in egg white were separated in a single run. The microheterogeneities of OVA could also be found in it. The separation efficiency for the main peak of OVA in egg white was around 10,000 plates/m.
Collapse
Affiliation(s)
- Yi-Ling Hsieh
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | | | | |
Collapse
|
32
|
Huang YF, Huang CC, Hu CC, Chang HT. Capillary electrophoresis-based separation techniques for the analysis of proteins. Electrophoresis 2006; 27:3503-22. [PMID: 16927348 DOI: 10.1002/elps.200600100] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
CE offers the advantages of high speed, great efficiency, as well as the requirement of minimum amounts of sample and buffer for the analysis of proteins. In this review, we summarize the CE-based techniques coupled with absorption, LIF, and MS detection systems for the analysis of proteins mostly within the past 5 years. The basic principle of each technique and its advantages and disadvantages for protein analysis are discussed in brief. Advanced CE techniques, including on-column concentration techniques and high-efficiency multidimensional separation techniques, for high-throughput protein profiling of complex biological samples and/or of single cells are emphasized. Although the developed techniques provide improved peak capacity, they have not become practical tools for proteomics, mainly because of poor reproducibility, low-sample lading capacity, and low throughput due to ineffective interfaces between two separation dimensions and that between separation and MS systems. In order to identify the complexities and dynamics of the proteomes expressed by cells, tissues, or organisms, techniques providing improved analytical sensitivity, throughput, and dynamic ranges are still demanded.
Collapse
Affiliation(s)
- Yu-Fen Huang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | | | | | | |
Collapse
|
33
|
Belenkii BG. Monolithic stationary phases: Yesterday, today, and tomorrow. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2006. [DOI: 10.1134/s1068162006040029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
34
|
Abstract
In this review research papers on the application of CEC are summarized that have been published between May 2003 and May 2005. First, a short overview is given of trends and developments in CEC that may increase the applicability of the separation technique. Next, application-oriented research using CEC is described in biochemical studies, including proteomics and genomics, in the analysis of food and natural products, and in pharmaceutical, industrial, and environmental analysis.
Collapse
Affiliation(s)
- Sebastiaan Eeltink
- Polymer-Analysis Group, van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Amsterdam, The Netherlands
| | | |
Collapse
|
35
|
Okanda FM, El Rassi Z. Affinity monolithic capillary columns for glycomics/proteomics: 1. Polymethacrylate monoliths with immobilized lectins for glycoprotein separation by affinity capillary electrochromatography and affinity nano-liquid chromatography in either a single column or columns coupled in series. Electrophoresis 2006; 27:1020-30. [PMID: 16470784 DOI: 10.1002/elps.200500766] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this report, microcolumn separation schemes involving monolithic capillary columns with immobilized lectins, and relevant to nanoglycomics/nanoproteomics were introduced. Positive and neutral monoliths based on poly(glycidyl methacrylate-co-ethylene dimethacrylate) were designed for achieving lectin affinity chromatography (LAC) by nano-LC and CEC. The positive monoliths (i.e., monoliths with cationic sites) afforded relatively high permeability in nano-LC but lack predictable EOF magnitude and direction, while neutral monoliths provided a good compromise between reasonable permeability in nano-LC and predictable EOF in CEC. Lectin affinity nano-LC permitted the enrichment of classes of different glycoproteins having similar N-glycans recognized by the immobilized lectin, whereas lectin affinity CEC provided the simultaneous capturing and separation of different glycoproteins due to differences in charge-to-mass ratio. Also, this investigation demonstrated for the first time the coupling of lectin capillary columns in series (i.e., tandem columns) for enhanced separation of glycoproteins by LAC using the CEC modality. Furthermore, in the coupled columns format, glycoforms of a given glycoprotein were readily separated.
Collapse
Affiliation(s)
- Fred M Okanda
- Department of Chemistry, Oklahoma State University, Stillwater, OK, USA
| | | |
Collapse
|
36
|
Okanda FM, El Rassi Z. Capillary electrochromatography with monolithic stationary phases. 4. Preparation of neutral stearyl-acrylate monoliths and their evaluation in capillary electrochromatography of neutral and charged small species as well as peptides and proteins. Electrophoresis 2005; 26:1988-95. [PMID: 15841500 DOI: 10.1002/elps.200500073] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A neutral, nonpolar monolithic capillary column having a relatively strong electroosmotic flow (EOF) yet free of electrostatic interactions with charged solutes was developed for the reversed-phase capillary electrochromatography (RP-CEC) of neutral and charged species including peptides and proteins. The neutral nonpolar monolith is based on the in situ polymerization of pentaerythritol diacrylate monostearate (PEDAS) in a ternary porogenic solvent composed of cyclohexanol, ethylene glycol, and water. PEDAS plays the role of both the cross-linker and the ligand provider, generating a macroporous nonpolar monolith having C17 chains as the chromatographic ligands. Despite the fact that the neutral PEDAS monolith is devoid of fixed charges, the monolithic capillary columns exhibited a relatively strong EOF due to the ability of PEDAS to adsorb sufficient amounts of electrolyte ions from the mobile phase. The adsorbed ions imparted the neutral PEDAS monolith the zeta potential necessary to support the EOF required for mass transport across the monolithic column. The absence of fixed charges on the surface of the neutral PEDAS monolith and in turn the adsorption sites for electrostatic attraction of charged solutes allowed the rapid and efficient separations of proteins and peptides at pH 7.0, with an average plate number of 255,000 and 121,000 plates/m, respectively. To the best of our knowledge, this constitutes the first report on the separation of proteins at neutral pH by RP-CEC using a neutral monolithic column.
Collapse
Affiliation(s)
- Fred M Okanda
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA
| | | |
Collapse
|
37
|
Channer B, Skellern GG, Euerby MR, McKeown AP, Rathore AS. Migration behavior of weakly retained, charged analytes in voltage-assisted micro-high performance liquid chromatography. J Chromatogr A 2005; 1095:172-9. [PMID: 16275298 DOI: 10.1016/j.chroma.2005.07.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 07/20/2005] [Accepted: 07/29/2005] [Indexed: 11/29/2022]
Abstract
The application of voltage in micro-high performance liquid chromatography (micro-HPLC) creates a system where separation is governed by a hybrid differential migration process, which entails the features of both HPLC and capillary zone electrophoresis (CZE), i.e., chromatographic retention and electrophoretic migration. In this paper, we use our previously published approach to decouple these two mechanisms via analysis of the input data for estimation of electrokinetic parameters, such as conductivity, equivalent lengths, mobilities and velocities. Separation of weakly retained, charged analytes was performed via voltage-assisted micro-HPLC. Contrary to conclusions from data analysis using the conventional definitions of the retention factor, it is shown that our approach allows us to isolate the "chromatographic retention" component and thus, investigate the "modification" of the retention process upon application of voltage in micro-HPLC. It is shown that the traditional approaches of calculating retention factor would erroneously lead to conclusion that the retention behavior of these analytes changes upon application of voltage. However, the approach suggested here demonstrates that under the conditions investigated, most of the charged analytes do not show any significant retention on the columns and that all the changes in their retention times can be attributed to their electrophoretic migration.
Collapse
Affiliation(s)
- Barbara Channer
- Department of Pharmaceutical Sciences, University of Strathclyde, The John Arbuthnott Building, Glasgow, Scotland, UK
| | | | | | | | | |
Collapse
|
38
|
Waguespack BL, Hodges SA, Bush ME, Sondergeld LJ, Bushey MM. Capillary electrochromatography column behavior of butyl and lauryl acrylate porous polymer monoliths. J Chromatogr A 2005; 1078:171-80. [PMID: 16007995 DOI: 10.1016/j.chroma.2005.04.083] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A variety of porous polymer monoliths (PPMs) have been synthesized using the 'conduct-as-cast' format. The resulting polymers have been evaluated for use as separation media in capillary electrochromatography (CEC). The results have shown that substituting a small percentage of the standard polymer formulation with a more hydrophobic monomer produced columns with expected increases in retention for a neutral analyte series. However, substituting larger percentages of a more hydrophobic monomer resulted in columns that exhibited less retention. The unexpected behavior of these hydrophobic columns has been attributed to the non-uniform polymeization of the moree hydrophobic monoliths. Van Deemter plots of polyaromatic hydrocarbons have been examined to further analyze the unexpected behavior of these columns. Hmin values ranged from 8.7 to 9.1 microm for the columns evaluated. The effect of the percentage of organic modfier in the phase on the separation has also been studied. The retention window decreases when altering the ACN concentration in the mobile phase from 50% to 80% (v/v).
Collapse
Affiliation(s)
- Brent L Waguespack
- Department of Chemistry, Trinity University, One Trinity Place, San Antonio, TX 78212-7200, USA
| | | | | | | | | |
Collapse
|
39
|
Abstract
The sequencing of several organisms' genomes, including the human's one, has opened the way for the so-called postgenomic era, which is now routinely coined as "proteomics". The most basic task in proteomics remains the detection and identification of proteins from a biological sample, and the most traditional way to achieve this goal consists of protein separations performed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Still, the 2-D PAGE-mass spectrometry (MS) approach remains lacking in proteome coverage (for proteins having extreme isoelectric points or molecular masses as well as for membrane proteins), dynamic range, sensitivity, and throughput. Consequently, considerable efforts have been devoted to the development of non-gel-based proteome separation technologies in an effort to alleviate the shortcomings in 2-D PAGE while reserving the ability to resolve complex protein and peptide mixtures prior to MS analysis. This review focuses on the most recent advances in capillary-based separation techniques, including capillary liquid chromatography, capillary electrophoresis, and capillary electrokinetic chromatography, and combinations of multiples of these mechanisms, along with the coupling of these techniques to MS. Developments in capillary separations capable of providing extremely high resolving power and selective analyte enrichment are particularly highlighted for their roles within the broader context of a state-of-the-art integrated proteome effort. Miniaturized and integrated multidimensional peptide/protein separations using microfluidics are further summarized for their potential applications in high-throughput protein profiling toward biomarker discovery and clinical diagnosis.
Collapse
|
40
|
Bedair M, El Rassi Z. Recent advances in polymeric monolithic stationary phases for electrochromatography in capillaries and chips. Electrophoresis 2004; 25:4110-9. [PMID: 15597411 DOI: 10.1002/elps.200406136] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This review article summarizes the advances made over the last two years in polymeric monoliths for capillary electrochromatography (CEC). It covers the scientific literature in the period extending form the second half of 2002 until the end of first half of 2004. Currently, there is an increasing interest in monolithic stationary phases in CEC as an alternative to particulate packed capillary columns due in major part to the simplicity of the in situ preparation of monolithic stationary phases and the availability of a wide chemistry for surface ligands, which allow for tailoring the chromatographic sorbent needed for solving a given separation problem(s). The various approaches, formats, and chemistries used for the preparation of monolithic stationary phases are described.
Collapse
Affiliation(s)
- Mohamed Bedair
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA
| | | |
Collapse
|
41
|
Abstract
This review surveys the accomplishments in the separation of peptides and proteins by capillary electrochromatography (CEC) over the last decade. A significant number of research articles have been published on this topic since the last review. Peptide and proteins separations have been carried out in all three formats of CEC, i.e., packed bed, continuous bed and open-tubular (OT) format. In addition to electrophoresis, different chromatographic modes have been successfully exploited with the most prevalent being reversed-phase mode followed by ion-exchange. Although many researchers continue to use model proteins and peptides primarily to evaluate the performance of novel stationary phases some researchers have also applied CEC to the analysis of real-life samples. The potential of CEC to yield complementary information and sometimes a superior separation with respect to established techniques, i.e., microbore HPLC and capillary electrophoresis has been demonstrated. Instrumental modifications in order to facilitate coupling of CEC to mass spectrometry have further upgraded the value of CEC for proteomic analysis. Capillaries are still the separation vehicle of choice for most researchers yet the microfluidic platform is gaining momentum, propelled particularly by its potential for multitasking, e.g., performing different chromatographic modes in series.
Collapse
Affiliation(s)
- Dirk Bandilla
- Department of Chemistry and Biochemistry, Concordia University, Montréal, Que, H4B 1R6 Canada
| | | |
Collapse
|
42
|
Hilder EF, Svec F, Fréchet JMJ. Development and application of polymeric monolithic stationary phases for capillary electrochromatography. J Chromatogr A 2004; 1044:3-22. [PMID: 15354426 DOI: 10.1016/j.chroma.2004.04.057] [Citation(s) in RCA: 191] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Monolithic columns for capillary electrochromatography are receiving quite remarkable attention. This review summarizes results excerpted from numerous papers concerning this rapidly growing area with a focus on monoliths prepared from synthetic polymers. Both the simplicity of the in situ preparation and the large number of readily available chemistries make the monolithic separation media a vital alternative to capillary columns packed with particulate materials. Therefore, they are now a well-established stationary phase format in the field of capillary electrochromatography. A wide variety of synthetic approaches as well as materials used for the preparation of the monolithic stationary phases are presented in detail. The analytical potential of these columns is demonstrated with separations involving various families of compounds and different chromatographic modes.
Collapse
Affiliation(s)
- Emily F Hilder
- EO Lawrence Berkeley National Laboratory, Materials Sciences Division, Berkeley, CA 94720, USA
| | | | | |
Collapse
|