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Šolínová V, Tůma P, Butnariu M, Kašička V, Koval D. Covalent anionic copolymer coatings with tunable electroosmotic flow for optimization of capillary electrophoretic separations. Electrophoresis 2022; 43:1953-1962. [DOI: 10.1002/elps.202200130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/28/2022] [Accepted: 08/08/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Veronika Šolínová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 Czech Republic
| | - Petr Tůma
- Department of Hygiene, Third Faculty of Medicine Charles University Prague 10 Czech Republic
| | - Maria Butnariu
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 Czech Republic
- Department of Analytical Chemistry, Faculty of Science Charles University Prague 2 Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 Czech Republic
| | - Dušan Koval
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Prague 6 Czech Republic
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2
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Meyer S, Clases D, Gonzalez de Vega R, Padula MP, Doble PA. Separation of intact proteins by capillary electrophoresis. Analyst 2022; 147:2988-2996. [PMID: 35673805 DOI: 10.1039/d2an00474g] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work introduces novel and universal workflows for the analysis of intact proteins by capillary electrophoresis and presents guidelines for the targeted selection of appropriate background electrolytes (BGEs) by consideration of the target proteins' isoelectric point (pI). The suitability of neutral dimethyl polysiloxane (PDMS) capillaries with dynamic coatings of cationic cetyltrimethylammonium bromide (CTAB) or anionic sodium dodecyl sulfate (SDS), and bare fused silica (BFS) capillaries were systematically evaluated for the analysis of histidine and seven model proteins in six BGEs with pH values between 3.0 and 9.6. Multiple capillary and BGE combinations were suitable for the analysis of all proteins with molecular weights ranging from 13.7-150 kDa, and pIs between 4.7 and 9.6. The CTAB-PDMS capillary was best suited for low pH BGEs, while the SDS-PDMS and BFS capillary were superior for high pH BGEs. These combinations consistently resulted in sharp peak shapes and rapid migration times. pH values of BGEs closer to the proteins' pI produced poorer peak shapes and decreased effective mobilities due to suppressed ionisation. Plots of mobility vs. pH crossed at approximately the pI of the protein in most cases. The workflow was applied to the analysis of caseins and whey proteins in milk for the separation of the seven most abundant proteins, including the isoforms of A1 and A2 β-casein and β-lactoglobulin A and B.
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Affiliation(s)
- Sarah Meyer
- The Atomic Medicine Initiative, University of Technology Sydney, Sydney, NSW, Australia.
| | - David Clases
- Institute of Chemistry, University of Graz, Graz, Austria
| | | | - Matthew P Padula
- School of Life Sciences and Proteomics, Lipidomics and Metabolomics Core Facility, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - Philip A Doble
- The Atomic Medicine Initiative, University of Technology Sydney, Sydney, NSW, Australia.
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3
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Terashima H, Yamamoto A, Aizawa SI, Taga A, Mikami I, Ishihara Y, Kodama S. Enantioseparation of phenethylamines by using high-performance liquid chromatography column permanently coated with methylated β-cyclodextrin. J Sep Sci 2021; 44:2932-2940. [PMID: 34077621 DOI: 10.1002/jssc.202100343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/28/2021] [Accepted: 05/29/2021] [Indexed: 01/13/2023]
Abstract
Cyclodextrins and their derivatives have been used for chiral high-performance liquid chromatography selectors, while they are costly to use as mobile phase additives in high-performance liquid chromatography. Here, we report application of phenyl column coated permanently with methylated β-cyclodextrin for chiral high-performance liquid chromatography. A 0.1% (v/v) phosphoric acid solution containing 1 M NaCl and 0.5% (w/v) methylated β-cyclodextrin was subjected to a phenyl column at a flow rate of 0.5 mL/min at 30°C for 2 h. Using the precoating phenyl column, all the enantiomers of the four phenethylamines (norepinephrine, epinephrine, octopamine, and synephrine) were successfully separated simultaneously by high-performance liquid chromatography with a mobile phase without methylated β-cyclodextrin at a flow rate of 0.2 mL/min at 30°C. The enantioseparation ability was retained for successive analyses during 1 week. It is suggested that inclusion complex of methylated β-cyclodextrin with a phenyl group on the surface of the stationary phase could be formed and that the inclusion complex could form the ternary complex with the injected analytes. The longer retention time of (S)-enantiomers of analytes than corresponding (R)-enantiomers for high-performance liquid chromatography could be explained from the higher stability of the methylated β-cyclodextrin complexes with (S)-enantiomers, which were confirmed by capillary electrophoresis and 1 H NMR spectroscopy experiments.
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Affiliation(s)
| | - Atsushi Yamamoto
- Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, Aichi, Japan
| | | | - Atsushi Taga
- Faculty of Pharmacy, Kindai University, Higashi-Osaka, Japan
| | - Ikko Mikami
- School of Science, Tokai University, Hiratsuka, Japan
| | | | - Shuji Kodama
- School of Science, Tokai University, Hiratsuka, Japan
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4
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Guo C, Zhang Q, Bao L, Li H, Zheng Q, Guo Z, Chen Y. A stable version of capillary electrophoresis for determining human hemoglobin chains aiming at the screening and diagnosis of thalassemia. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2020; 12:3277-3284. [PMID: 32930191 DOI: 10.1039/d0ay00384k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
As a fast, high-performance and cost-effective separation technique, capillary electrophoresis (CE) is applicable to the screening and diagnosis of diseases such as thalassemia. However, it is often not preferred due to its unrepeatable and/or irreproducible migration times. Herein, we propose a stable version of CE that uses migration charge density instead of the migration time to plot the electropherogram. The peak position is now independent of the applied voltage or current and the capillary geometry and is also insensitive to temperature. Its applicability was demonstrated in the quantitative analysis of human hemoglobin. On a laboratory-built device, with a running buffer simply consisting of 3.0 M acetic acid and 0.1% (w/v) hydroxyethyl cellulose, it allows a direct injection of whole blood samples and all the concerned globin chains, α, β, Aγ and Gγ can be well separated in 15 minutes. The resolution of α/β, β/Aγ, and Aγ/Gγ reached 4.4, 3.1 and 5.3, respectively. The intra- and inter-day precisions for the peak position based on the migration charge densities were below 0.6%. Its diagnostic applicability was validated in the analysis of several real blood samples from newborns, children and adults, and its capacity was demonstrated to screen and define the type of thalassemia.
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Affiliation(s)
- Chao Guo
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qianchun Zhang
- Key Laboratory of Chemical Synthesis and Environmental Pollution Control-Remediation Technology of Guizhou Province, School of Biology and Chemistry, Xingyi Normal University for Nationalities, Xingyi 562400, China
| | - Linchun Bao
- Clinical Laboratory, Qian Xi Nan People's Hospital, Xingyi 562400, China
| | - Hongliang Li
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingfeng Zheng
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhenpeng Guo
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Chen
- Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing National Laboratory for Molecular Sciences, Beijing 100190, China
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5
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Haridasan N, Kannam SK, Mogurampelly S, Sathian SP. Translational mobilities of proteins in nanochannels: A coarse-grained molecular dynamics study. Phys Rev E 2018; 97:062415. [PMID: 30011556 DOI: 10.1103/physreve.97.062415] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Indexed: 05/18/2023]
Abstract
We investigated the translation of a protein through model nanopores using coarse-grained (CG) nonequilibrium molecular dynamics (NEMD) simulations and compared the mobilities with those obtained from previous coarse-grained equilibrium molecular dynamics model. We considered the effects of nanopore confinement and external force on the translation of streptavidin through nanopores of dimensions representative of experiments. As the nanopore radius approaches the protein hydrodynamic radius, r_{h}/r_{p}→1 (where r_{h} is the hydrodynamic radius of protein and r_{p} is the pore radius), the translation times are observed to increase by two orders of magnitude. The translation times are found to be in good agreement with the one-dimensional biased diffusion model. The results presented in this paper provide useful insights on nanopore designs intended to control the motion of biomolecules.
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Affiliation(s)
- Navaneeth Haridasan
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sridhar Kumar Kannam
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- School of Sciences, RMIT University, Melbourne, Victoria 3001, Australia
| | - Santosh Mogurampelly
- Institute for Computational Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Sarith P Sathian
- Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036, India
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Mao K, Du H, Bai L, Zhang Y, Zhu H, Wang Y. Poly (2-methyl-2-oxazoline) coating by thermally induced immobilization for determination of bovine lactoferrin in infant formula with capillary electrophoresis. Talanta 2017; 168:230-239. [DOI: 10.1016/j.talanta.2017.03.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 03/10/2017] [Accepted: 03/16/2017] [Indexed: 11/16/2022]
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7
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Dawod M, Arvin NE, Kennedy RT. Recent advances in protein analysis by capillary and microchip electrophoresis. Analyst 2017; 142:1847-1866. [PMID: 28470231 PMCID: PMC5516626 DOI: 10.1039/c7an00198c] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
This review article describes the significant recent advances in the analysis of proteins by capillary and microchip electrophoresis during the period from mid-2014 to early 2017. This review highlights the progressions, new methodologies, innovative instrumental modifications, and challenges for efficient protein analysis in human specimens, animal tissues, and plant samples. The protein analysis fields covered in this review include analysis of native, reduced, and denatured proteins in addition to Western blotting, protein therapeutics and proteomics.
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Affiliation(s)
- Mohamed Dawod
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, Michigan 48109, USA.
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8
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Hajba L, Guttman A. Recent advances in column coatings for capillary electrophoresis of proteins. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.02.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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9
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Bodnar J, Hajba L, Guttman A. A fully automated linear polyacrylamide coating and regeneration method for capillary electrophoresis of proteins. Electrophoresis 2016; 37:3154-3159. [PMID: 27731499 DOI: 10.1002/elps.201600405] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 09/09/2016] [Accepted: 09/10/2016] [Indexed: 11/07/2022]
Abstract
Surface modification of the inner capillary wall in CE of proteins is frequently required to alter EOF and to prevent protein adsorption. Manual protocols for such coating techniques are cumbersome. In this paper, an automated covalent linear polyacrylamide coating and regeneration process is described to support long-term stability of fused-silica capillaries for protein analysis. The stability of the resulting capillary coatings was evaluated by a large number of separations using a three-protein test mixture in pH 6 and 3 buffer systems. The results were compared to that obtained with the use of bare fused-silica capillaries. If necessary, the fully automated capillary coating process was easily applied to regenerate the capillary to extend its useful life-time.
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Affiliation(s)
- Judit Bodnar
- MTA-PE Translational Glycomics Research Group, University of Pannonia, Veszprem, Hungary
| | - Laszlo Hajba
- MTA-PE Translational Glycomics Research Group, University of Pannonia, Veszprem, Hungary
| | - Andras Guttman
- MTA-PE Translational Glycomics Research Group, University of Pannonia, Veszprem, Hungary.,Horváth Csaba Memorial Institute for Bioanalytical Research, University of Debrecen, Debrecen, Hungary
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10
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Abstract
Peptides are an important class of analytes in chemistry, biochemistry, food chemistry, as well as medical and pharmaceutical sciences including biomarker analysis in peptidomics and proteomics. As a high-resolution technique, capillary electrophoresis (CE) is well suited for the analysis of polar compounds such as peptides. In addition, CE is orthogonal to high-performance liquid chromatography (HPLC) as both techniques are based on different physicochemical separation principles. For the successful development of peptide separations by CE, operational parameters including puffer pH, buffer concentration and buffer type, applied voltage, capillary dimensions, as well as background electrolyte additives such as detergents, ion-pairing reagents, cyclodextrins, (poly)amines, and soluble polymers have to be considered and optimized.
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Affiliation(s)
- Gerhard K E Scriba
- Department of Pharmaceutical Chemistry, University of Jena, Philosophenweg 14, Jena, 07743, Germany.
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11
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El-Debs R, Nehmé R, Claude B, Motteau S, Togola A, Berho C, Morin P. Coated capillaries with highly charged polyelectrolytes and carbon nanotubes co-aggregated with sodium dodecyl sulphate for the analysis of sulfonylureas by capillary electrophoresis. J Chromatogr A 2014; 1367:161-6. [DOI: 10.1016/j.chroma.2014.09.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 11/28/2022]
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12
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Pobozy E, Sentkowska A, Piskor A. Comparison of three modifications of fused-silica capillaries and untreated capillaries for protein profiling of maize extracts by capillary electrophoresis. J Sep Sci 2014; 37:2388-94. [PMID: 24931305 DOI: 10.1002/jssc.201301236] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 06/02/2014] [Accepted: 06/03/2014] [Indexed: 12/15/2022]
Abstract
In this work, capillary electrophoresis was applied to protein profiling of fractionated extracts of maize. A comparative study on the application of uncoated fused-silica capillaries and capillaries modified with hydroxypropylmethylcellulose, ω-iodoalkylammonium salt and a commercially available neutral capillary covalently coated with polyacrylamide is presented. The coating stability, background electrolyte composition, and separation efficiency were investigated. It was found that for zeins separation, the most stable and efficient was the capillary coated with polyacrylamide. Finally, the usefulness of these methods was studied for the differentiation of zein fraction in transgenic and nontransgenic maize. Zeins extracted from maize standards containing 0 and 5% m/m genetic modification were successfully separated, but slight differences were observed in terms of the zein content. Albumin and globulin fractions were analyzed with the use of unmodified fused-silica capillary with borate buffer pH 9 and the capillary coated with polyacrylamide with phosphate buffer pH 3. In the albumin fraction, additional peaks were found in genetically modified samples.
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Affiliation(s)
- Ewa Pobozy
- Department of Chemistry, Warsaw University, Warsaw, Poland
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13
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Tůma P. Rapid determination of globin chains in red blood cells by capillary electrophoresis using INSTCoated fused-silica capillary. J Sep Sci 2014; 37:1026-32. [DOI: 10.1002/jssc.201400044] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/05/2014] [Accepted: 02/05/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Petr Tůma
- Institute of Biochemistry; Cell and Molecular Biology, Third Faculty of Medicine, Charles University; Prague 10 Czech Republic
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Sáiz J, Mai TD, Hauser PC, García-Ruiz C. Determination of nitrogen mustard degradation products in water samples using a portable capillary electrophoresis instrument. Electrophoresis 2013; 34:2078-84. [PMID: 23686627 DOI: 10.1002/elps.201300054] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 05/10/2013] [Accepted: 05/10/2013] [Indexed: 12/26/2022]
Abstract
In this work, a new purpose-made portable CE instrument with a contactless conductivity detector was used for the determination of degradation products of nitrogen mustards in different water samples. The capillary was coated with poly(1-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate) to avoid analyte-wall interactions. The coating procedure was studied to obtain the best repeatability of the migration time of the analytes. Four different coating procedures were compared; flushing the capillary with the copolymer at 100 psi for 2 min at 60°C provided the best RSD values (<4%). The analytical method was also optimized. The use of 20 mM of MES adjusted to pH 6.0 with His as running buffer allowed a good baseline separation of the three analytes in different water samples without matrix interferences. The method permitted the detection of the three degradation products down to 5 μM.
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Affiliation(s)
- Jorge Sáiz
- Department of Analytical Chemistry, Multipurpose Building of Chemistry, University of Alcalá, Alcalá de Henares, Madrid, Spain
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Nehmé R, Perrin C. Highly charged polyelectrolyte coatings to prevent adsorption during protein and peptide analysis in capillary electrophoresis. Methods Mol Biol 2013; 984:191-206. [PMID: 23386345 DOI: 10.1007/978-1-62703-296-4_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Capillary electrophoresis (CE) is an interesting technique for protein and peptide analysis. However, one of the major problems concerns sample adsorption on the internal capillary wall. The use of non-covalent coatings using highly charged polyelectrolytes is an efficient, simple, and fast approach to reduce peptide and protein adsorption phenomena. We have studied in a systematic manner the effect of coating conditions on the stability and efficiency of multilayer coatings using poly(diallyldimethylammonium) chloride (PDADMAC) as polycation and polystyrene sulfonate (PSS) as polyanion. When optimal conditions defined in the protocols are used, very stable coatings are obtained and adsorption phenomena are eliminated. The coatings are stable over a large range of pH buffer (2-10) and in the presence of organic solvent. Hundreds of analyses can be performed without coating regeneration. Coated capillaries can be easily stored and reused.
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Affiliation(s)
- Reine Nehmé
- Institut de Chimie Organique et Analytique (ICOA), Université d'Orléans, UMR CNRS 7311, Orléans, France
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de Jong S, Epelbaum N, Liyanage R, Krylov SN. A semipermanent coating for preventing protein adsorption at physiological pH in kinetic capillary electrophoresis. Electrophoresis 2012; 33:2584-90. [DOI: 10.1002/elps.201200153] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Lindenburg PW, Tempels FA, Tjaden UR, van der Greef J, Hankemeier T. On-line large-volume electroextraction coupled to liquid chromatography–mass spectrometry to improve detection of peptides. J Chromatogr A 2012; 1249:17-24. [DOI: 10.1016/j.chroma.2012.06.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 05/18/2012] [Accepted: 06/06/2012] [Indexed: 10/28/2022]
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18
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Rocheleau MJ, Larouche E, Salamu C, Curca M. Impurity profiling and in-process testing of drugs for injection by fast liquid chromatography. J Pharm Anal 2012; 2:372-377. [PMID: 29403769 PMCID: PMC5760775 DOI: 10.1016/j.jpha.2012.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 07/11/2012] [Indexed: 11/26/2022] Open
Abstract
Liquid chromatography (LC) is considered by many as a mature technique. Nonetheless, LC technology continues to evolve driven by the need for high-throughput and high-resolution analyses. Over the past several years, small particle size packing materials have been introduced by several column manufacturers to enable fast and efficient LC separations. Several examples of pharmaceutical analyses, including impurity profiling of taxanes and atracurium besylate, in-process testing of peptides in injectable dosage form, using sub-2 μm column technology are presented in this paper, demonstrating some of the capabilities and limitations of the technology.
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Affiliation(s)
| | - Elaine Larouche
- Omega Laboratories Ltd., 11177 Hamon, Montréal, QC H3M 3E4, Canada
| | - Cristina Salamu
- Omega Laboratories Ltd., 11177 Hamon, Montréal, QC H3M 3E4, Canada
| | - Mihaela Curca
- Omega Laboratories Ltd., 11177 Hamon, Montréal, QC H3M 3E4, Canada
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Pan Q, Hong S, Zhu X, Zhao M, Lee LP. On-line electrophoretic sample clean-up for sensitive and reproducible μCE immunoassay. LAB ON A CHIP 2012; 12:932-938. [PMID: 22278032 DOI: 10.1039/c2lc21111d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report a novel on-line electrophoretic sample clean-up approach for highly sensitive and reproducible microchip electrophoretic (μCE) immunoassay of low-abundance proteins in human serum. The method takes advantage of the differential effect of field-amplified sample stacking on molecules with different electrophoretic mobility. Large interfering proteins are removed from the loading channel by simple voltage control, resulting in selective concentration and injection of smaller target analytes to the separation channel. As a proof of concept, an antibody-free injection mode was developed for direct μCE immunoassay of human insulin-like growth factor-I (IGF-I) in serum samples without any additional purification steps. Clear and sharp peaks were obtained for IGF-I with low background and excellent reproducibility. Besides, the assay sensitivity was further increased by addition of ethanol to the sample buffer at a concentration of 50% right before performing the μCE detection. The lower limit of detection of IGF-I achieved 0.68 ng mL(-1), with an overall signal enhancement factor of 2750. The established on-line electrophoretic sample clean-up approach may find wide applications in the development of other microchip-based high-throughput analytical platforms for clinical and biological use.
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Affiliation(s)
- Qiong Pan
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
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Ryvolova M, Adam V, Kizek R. Analysis of metallothionein by capillary electrophoresis. J Chromatogr A 2012; 1226:31-42. [DOI: 10.1016/j.chroma.2011.10.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 09/30/2011] [Accepted: 10/01/2011] [Indexed: 02/05/2023]
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Kanoatov M, Retif C, Cherney LT, Krylov SN. Peak-shape correction to symmetry for pressure-driven sample injection in capillary electrophoresis. Anal Chem 2011; 84:149-54. [PMID: 22118024 DOI: 10.1021/ac203129h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pressure-driven sample injection in capillary electrophoresis results in asymmetric peaks due to difference in shapes between the front and the back boundaries of the sample plug. Uneven velocity profile of fluid flow across the capillary gives the front boundary a parabolic shape. The back side, on the other hand, has a flat interface with the electrophoresis run buffer. Here, we propose a simple means of correcting this asymmetry by pressure-driven "propagation" of the injected plug, with the parabolic sample-buffer interface established at the back. We prove experimentally that such a propagation procedure corrects peak asymmetry to the level comparable to injection through electroosmosis. Importantly, the propagation-based correction procedure also solves a problem of transferring the sample into the efficiently cooled zone of the capillary for capillary electrophoresis (CE) instruments with active cooling. The suggested peak correction procedure will find applications in all CE methods that rely on peak shape analysis, e.g., nonequilibrium capillary electrophoresis of equilibrium mixtures.
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Affiliation(s)
- Mirzo Kanoatov
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
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22
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Gowri VS, Almeida L, Amorim T, Carneiro N, Souto AP, Esteves MF. Novel copolymer for SiO2 nanoparticles dispersion. J Appl Polym Sci 2011. [DOI: 10.1002/app.35068] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Bachmann S, Bakry R, Huck CW, Polato F, Corradini D, Bonn GK. Peptide mapping using capillary electrophoresis offline coupled to matrix-assisted laser desorption ionization time of flight mass spectrometry. Electrophoresis 2011; 32:2830-9. [PMID: 21953317 DOI: 10.1002/elps.201000653] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 03/14/2011] [Accepted: 03/14/2011] [Indexed: 01/20/2023]
Abstract
This article reports the results of a study carried out to evaluate the offline hyphenation of capillary zone electrophoresis with matrix-assisted lased desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) for the analysis of low-abundant complex samples, represented by the tryptic phosphorylated peptides of phosphoproteins, such as α-casein, β-casein, and fetuin. The proposed method employs a latex-coated capillary and consists in the online preconcentration of the tryptic peptides by a pH-mediated stacking method, their separation by capillary zone electrophoresis, and subsequent deposition of the separated analytes onto a MALDI target for their MS analysis. The online preconcentration method allows loading a large sample volume (∼150 nL), which is introduced into the capillary after the hydrodynamic injection of a short plug of 1.0 M ammonium hydroxide solution and is sandwiched between two plugs of the acidic background electrolyte solution (BGE) filling the capillary. The sample spotting of the separated analytes onto the MALDI target is performed either during or postseparation using an automatic spotting device connected to the exit of the separation capillary. The proposed method allows the separation and identification of multiphosphorylated peptides from other peptides and enables their identification at femtomole level with improved efficiency compared with LC approaches hyphenated to MS.
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Affiliation(s)
- Stefan Bachmann
- Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innsbruck, Austria
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24
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Protein glycosylation analysis with capillary-based electromigrative separation techniques. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s12566-010-0018-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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25
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Liu H, Han N, Zhang L, Du Y, Zhang W. Design and evaluation of capillary electrophoresis in dynamically coated capillaries coupled with chemiluminescence detection. Anal Chim Acta 2010; 680:48-53. [DOI: 10.1016/j.aca.2010.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Revised: 08/28/2010] [Accepted: 09/09/2010] [Indexed: 12/01/2022]
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26
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Polymeric ionic liquid as a dynamic coating additive for separation of basic proteins by capillary electrophoresis. Anal Chim Acta 2010; 674:243-8. [DOI: 10.1016/j.aca.2010.06.044] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 06/19/2010] [Accepted: 06/26/2010] [Indexed: 11/21/2022]
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27
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Spermine-graft-dextran non-covalent copolymer as coating material in separation of basic proteins and neurotransmitters by capillary electrophoresis. J Chromatogr A 2010; 1217:5130-6. [PMID: 20591436 DOI: 10.1016/j.chroma.2010.06.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 06/04/2010] [Accepted: 06/04/2010] [Indexed: 11/22/2022]
Abstract
Spermine-graft-dextran (Spe-g-Dex) copolymer was synthesized and used as a non-covalent coating for the separation of proteins and neurotransmitters by capillary electrophoresis. The coating was obtained via flushing the capillary with 1.0% Spe-g-Dex copolymer solution for 2min. Electroosmotic flow (EOF) was strongly suppressed, ranging from -1.60x10(-9) to 3.65x10(-9)m(2)V(-1)s(-1). Effect of experimental conditions, such as the copolymer concentration, the concentration and pH of the background electrolyte (BGE), on the Spe-g-Dex coating was investigated. Separation of lysozyme, cytochrome c, ribonuclease A and alpha-chymotrypsinogen yielded high separation efficiencies ranging from 141000 to 303000plates/m and recoveries from 85.4% to 98.3% at pH 4.0 (284.0mM sodium acetate-acetic acid buffer, I=50mM). Run-to-run repeatabilities and day-to-day, and capillary-to-capillary reproducibilities were all below 1.7%. In addition, Spe-g-Dex coating allowed the successful separation of five neurotransmitters, 5-hydroxytryptamine, dopamine, epinephrine, isoprenaline, dobuamine at pH 4.0 with high separation efficiencies of 290000-449000plates/m.
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28
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Wilken LR, Nikolov ZL. Evaluation of alternatives for human lysozyme purification from transgenic rice: Impact of phytic acid and buffer. Biotechnol Prog 2010; 26:1303-11. [DOI: 10.1002/btpr.434] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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29
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Elhamili A, Wetterhall M, Sjödin M, Sebastiano R, Bergquist J. Analysis of peptides usingN-methylpolyvinylpyridium as silica surface modifier for CE-ESI-MS. Electrophoresis 2010; 31:1151-1156. [DOI: 10.1002/elps.200900536] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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30
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Alahmad Y, Taverna M, Mobdi H, Duboeuf J, Grégoire A, Rancé I, Tran NT. A validated capillary electrophoresis method to check for batch-to-batch consistency during recombinant human glycosylated interleukin-7 production campaigns. J Pharm Biomed Anal 2010; 51:882-8. [DOI: 10.1016/j.jpba.2009.09.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 09/04/2009] [Accepted: 09/08/2009] [Indexed: 11/26/2022]
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31
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Bohoyo D, Le Potier I, Rivière C, Klafki H, Wiltfang J, Taverna M. A quantitative CE method to analyse tau protein isoforms using coated fused silica capillaries. J Sep Sci 2010; 33:1090-8. [DOI: 10.1002/jssc.200900713] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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32
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Bachmann S, Vallant R, Bakry R, Huck CW, Corradini D, Bonn GK. CE coupled to MALDI with novel covalently coated capillaries. Electrophoresis 2010; 31:618-29. [DOI: 10.1002/elps.200900507] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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33
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Nehmé R, Perrin C, Guerlavais V, Fehrentz JA, Cottet H, Martinez J, Fabre H. Use of coated capillaries for the electrophoretic separation of stereoisomers of a growth hormone secretagogue. Electrophoresis 2009; 30:3772-9. [DOI: 10.1002/elps.200900093] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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34
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Wang AJ, Witos J, D'Ulivo L, Vainikka K, Riekkola ML. Noncovalent poly(1-vinylpyrrolidone)-based copolymer coating for the separation of basic proteins and lipoproteins by CE. Electrophoresis 2009; 30:3939-46. [DOI: 10.1002/elps.200900395] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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35
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De Benedetto GE, Fanigliulo M. A new CE-ESI-MS method for the detection of stable hemoglobin acetaldehyde adducts, potential biomarkers of alcohol abuse. Electrophoresis 2009; 30:1798-807. [PMID: 19441035 DOI: 10.1002/elps.200800379] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new CE-ESI-MS method was developed to provide a simple way to study changes to hemoglobin (HbA) induced by acetaldehyde (Ach) in vitro. Instrumental parameters were univariately optimized in order to maximize the sensitivity of the CE-ESI-MS method. The electrophoretic separations were carried out in poly-E323-coated capillaries using 60 mM formic acid raised to pH 3.0 with ammonia and containing 5% 2-propanol while the sheath liquid, 2-propanol/water (30:70) with 0.1% formic acid, was delivered at 1.0 microL/min through a coaxial sheath flow electrospray interface. The HbA was incubated with Ach for intervals up to 24 h at concentration varying in the window 0.2-20 mM. Four stable Ach-hemoglobin adducts in the hemoglobin tryptic digest were observed at the submillimolar Ach concentration and characterized by MS/MS experiments: although the alpha and beta N-amino terminal modifications were expected, the two internal ones arising, respectively, from the condensation of Ach molecules on the histidine residue in position 4 in alpha4 (i.e. the fourth peptide after tryptic digestion of alpha chain starting from amino terminal) and on the asparagine residue in position 2 in beta3, were identified for the first time. During the in vitro experiments higher concentrations of Ach were also used; however, it was not possible to identify any other stable modification of hemoglobin. Interestingly, those stable modifications are the only ones in vivo identified in the hemoglobin of moderate alcohol drinkers.
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Affiliation(s)
- Giuseppe E De Benedetto
- Laboratorio di Analisi Chimiche per l'Ambiente e i Beni Culturali, Dipartimento dei Beni delle Arti e della Storia, Università del Salento, Lecce, Italy.
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36
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Huhn C, Ramautar R, Wuhrer M, Somsen GW. Relevance and use of capillary coatings in capillary electrophoresis–mass spectrometry. Anal Bioanal Chem 2009; 396:297-314. [DOI: 10.1007/s00216-009-3193-y] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 09/22/2009] [Accepted: 09/24/2009] [Indexed: 11/24/2022]
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37
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Alahmad Y, Thuy Tran N, Duboeuf J, Grégoire A, Rancé I, Taverna M. CZE for glycoform profiling and quality assessment of recombinant human interleukin-7. Electrophoresis 2009; 30:2347-54. [DOI: 10.1002/elps.200800789] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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38
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Nehmé R, Perrin C, Cottet H, Blanchin M, Fabre H. Influence of polyelectrolyte capillary coating conditions on protein analysis in CE. Electrophoresis 2009; 30:1888-98. [DOI: 10.1002/elps.200800688] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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39
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Ionic liquids used in and analyzed by capillary and microchip electrophoresis. J Chromatogr A 2009; 1216:4817-23. [DOI: 10.1016/j.chroma.2009.04.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 04/03/2009] [Accepted: 04/08/2009] [Indexed: 11/18/2022]
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40
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Stutz H. Protein attachment onto silica surfaces - a survey of molecular fundamentals, resulting effects and novel preventive strategies in CE. Electrophoresis 2009; 30:2032-61. [DOI: 10.1002/elps.200900015] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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41
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Kadar EP, Wujcik CE. Remediation of undesirable secondary interactions encountered in hydrophilic interaction chromatography during development of a quantitative LC–MS/MS assay for a dipeptidyl peptidase IV (DPP-IV) inhibitor in monkey serum. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:471-6. [DOI: 10.1016/j.jchromb.2008.11.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 11/17/2008] [Accepted: 11/26/2008] [Indexed: 01/08/2023]
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42
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Hou C, Herr AE. Clinically relevant advances in on-chip affinity-based electrophoresis and electrochromatography. Electrophoresis 2008; 29:3306-19. [DOI: 10.1002/elps.200800244] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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43
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Wu Y, Xie J, Wang F, Chen Z. Electrokinetic separation of peptides and proteins using a polyvinylamine-coated capillary with UV and ESI-MS detection. J Sep Sci 2008; 31:814-23. [DOI: 10.1002/jssc.200700518] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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44
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Analysis of human histone H4 by capillary electrophoresis in a pullulan-coated capillary, LC-ESI-MS and MALDI-TOF-MS. Anal Bioanal Chem 2008; 390:1881-8. [DOI: 10.1007/s00216-008-1903-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 12/18/2007] [Accepted: 01/21/2008] [Indexed: 10/22/2022]
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45
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Abstract
Peptides are an important class of analytes in chemistry, biochemistry, and food chemistry as well as medical and pharmaceutical sciences. As a high-resolution technique, capillary electrophoresis (CE) is well suited for the analysis of polar compounds such as peptides. In addition, CE is orthogonal to high-performance liquid chromatography, as both techniques are based on different physico-chemical separation principles. For the successful development of peptide separations by CE, operational parameters including buffer pH, buffer concentration and buffer type, applied voltage, and capillary dimensions, as well as background electrolyte additives such as detergents, ion-pairing reagents, cyclodextrins, (poly)amines, soluble polymers, etc. must be considered and optimized.
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Affiliation(s)
- Gerhard K E Scriba
- Department of Pharmaceutical Chemistry, University of Jena, Jena, Germany
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46
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Gómez JE, Sandoval JE. The effect of conditioning of fused-silica capillaries on their electrophoretic performance. Electrophoresis 2008; 29:381-92. [DOI: 10.1002/elps.200700577] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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47
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Ullsten S, Zuberovic A, Bergquist J. Adsorbed cationic polymer coatings for enhanced capillary electrophoresis/mass spectrometry of proteins. Methods Mol Biol 2008; 384:631-646. [PMID: 18392587 DOI: 10.1007/978-1-59745-376-9_25] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The combination of capillary electrophoresis (CE) with mass spectrometry (MS) constitutes a powerful microanalytical system for the analysis of biological samples. The anionic and hydrophobic surface of the fused-silica capillary is, however, known to cause severe analyte-wall interactions in protein analysis. In order to control surface properties and eliminate protein adsorption, a capillary coating can be applied. A fast and simple strategy is to coat the anionic capillary with a cationic polymer via multisite electrostatic interaction. This generates a stable deactivation layer, without the need for addition of coating agent to the background electrolyte solution. This chapter reviews the present knowledge of capillary coatings and especially cationic polymers in CE-MS, and describes the synthesis of a cationic polymer, PolyE-323, for deactivation of fused-silica capillaries. The capillary coating procedure is a simple three-step rinsing protocol comprising deprotonation of surface silanol groups using a base, adsorption of polymer, and a final rinse to remove excess polymer not adsorbed to the surface. As a result of the simplicity of the coating procedure, highly reproducible coatings can be prepared with little or no expert skills. Some practical aspects on using cationic-coated capillaries in CE-MS protein analysis are also discussed.
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Affiliation(s)
- Sara Ullsten
- Department of Analytical Chemistry, Biomedical Centre, Uppsala University, Uppsala, Sweden
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48
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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.
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Affiliation(s)
- Yu-Fen Huang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
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49
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Yu CJ, Tseng WL. Online concentration and separation of basic proteins using a cationic polyelectrolyte in the presence of reversed electroosmotic flow. Electrophoresis 2006; 27:3569-77. [PMID: 16915567 DOI: 10.1002/elps.200600121] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We report an online concentration and separation method for basic proteins using poly(diallyldimethylammonium chloride) (PDDA) solutions in the presence of reversed EOF. Using a capillary dynamically coated with 2% PDDA containing 0.1 M NaCl and filled with 1.2% PDDA under neutral conditions (10 mM phosphate, pH 7.0), we have demonstrated the separation of six basic proteins with peak efficiencies ranging from 175 000 to 616 000 plates/m and RSDs of migration time less than 0.4%. Additionally, high-speed separation of six basic proteins (<7 min) was achieved using a short capillary filled with 0.6% PDDA solutions. Under injection of the large-volume sample (210 nL), the LODs at S/N of 3 for basic proteins are down to nanomolar range. For example, the LOD for lysozyme is 1.2 nM, which is a 260-fold sensitivity enhancement compared with conventional injection method. The proposed method has been applied to the stacking of lysozyme in human saliva samples. Without any pretreatment, we also demonstrated the capability of this method to detect low amounts of peptide samples through the stacking of tryptic peptide of myoglobin. The experimental results indicate that our proposed method has great potential for use in clinical diagnosis and proteomics applications.
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Affiliation(s)
- Cheng-Ju Yu
- Department of Chemistry, National SunYat-sen University, Kaohsiung, Taiwan
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50
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Spanilá M, Pazourek J, Havel J. Electroosmotic flow changes due to interactions of background electrolyte counter-ions with polyethyleneimine coating in capillary zone electrophoresis of proteins. J Sep Sci 2006; 29:2234-40. [PMID: 17069254 DOI: 10.1002/jssc.200500461] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The properties and behavior of polyethyleneimine (PEI) covalently coated capillaries with respect to different background electrolytes used in capillary zone electrophoresis (CZE) are described. The coating stability and changes of inner surface charge in the capillary were followed by measurement of electroosmotic flow (EOF). Interest was focused mainly on conjugate bases of carboxylic acids as anionic background electrolyte components (acetate, citrate, malate, malonate, tartrate, and succinate). An interesting phenomenon was observed in PEI-coated capillaries: The direction (and the magnitude) of EOF depends on the composition of the background electrolyte and at a certain pH it can undergo reversible change. Ionic complex formation was suggested as a hypothesis to explain this behavior. With this knowledge, the PEI-coated capillary was used for the separation of basic proteins in the above-mentioned background electrolytes. A standard protein mixture of cytochrome c, ribonuclease A, and lysozyme at a concentration of 0.25 mg/mL each was chosen as model sample.
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Affiliation(s)
- Miroslava Spanilá
- Department of Analytical Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic.
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