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Long W, You M, Li J, Wang Y, Wang D, Tao X, Rao L, Xia Z, Fu Q. Sulfonic Functionalized Polydopamine Coatings with pH-Independent Surface Charge for Optimizing Capillary Electrophoretic Separations. Molecules 2024; 29:1600. [PMID: 38611879 PMCID: PMC11013714 DOI: 10.3390/molecules29071600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 03/30/2024] [Accepted: 03/31/2024] [Indexed: 04/14/2024] Open
Abstract
Enhancing the pH-independence and controlling the magnitude of electroosmotic flow (EOF) are critical for highly efficient and reproducible capillary electrophoresis (CE) separations. Herein, we present a novel capillary modification method utilizing sulfonated periodate-induced polydopamine (SPD) coating to achieve pH-independent and highly reproducible cathodic EOF in CE. The SPD-coated capillaries were obtained through post-sulfonation treatment of periodate-induced PDA (PDA-SP) coatings adhered on the capillary inner surface. The successful immobilization of the SPD coating and the substantial grafting of sulfonic acid groups were confirmed by a series of characterization techniques. The excellent capability of PDA-SP@capillary in masking silanol groups and maintaining a highly robust EOF mobility was verified. Additionally, the parameters of sulfonation affecting the EOF mobilities were thoroughly examined. The obtained optimum SPD-coated column offered the anticipated highly pH-independent and high-strength cathodic EOF, which is essential for enhancing the CE separation performance and improving analysis efficiency. Consequently, the developed SPD-coated capillaries enabled successful high-efficiency separation of aromatic acids and nucleosides and rapid cyclodextrin-based chiral analysis of racemic drugs. Moreover, the SPD-coated columns exhibited a long lifetime and demonstrated good intra-day, inter-day, and column-to-column repeatability.
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Affiliation(s)
- Wenwen Long
- School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Mingyue You
- School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Jieli Li
- School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Yan Wang
- School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Dan Wang
- School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Xueping Tao
- School of Pharmacy, Southwest Medical University, Luzhou 646000, China
| | - Li Rao
- Chongqing Key Laboratory of High Active Traditional Chinese Drug Delivery System, Chongqing Medical and Pharmaceutical College, Chongqing 401331, China
| | - Zhining Xia
- School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Qifeng Fu
- School of Pharmacy, Southwest Medical University, Luzhou 646000, China
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2
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Schwenzer AK, Kruse L, Jooß K, Neusüß C. Capillary electrophoresis-mass spectrometry for protein analyses under native conditions: Current progress and perspectives. Proteomics 2024; 24:e2300135. [PMID: 37312401 DOI: 10.1002/pmic.202300135] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/16/2023] [Accepted: 05/23/2023] [Indexed: 06/15/2023]
Abstract
Native mass spectrometry is a rapidly emerging technique for fast and sensitive structural analysis of protein constructs, maintaining the protein higher order structure. The coupling with electromigration separation techniques under native conditions enables the characterization of proteoforms and highly complex protein mixtures. In this review, we present an overview of current native CE-MS technology. First, the status of native separation conditions is described for capillary zone electrophoresis (CZE), affinity capillary electrophoresis (ACE), and capillary isoelectric focusing (CIEF), as well as their chip-based formats, including essential parameters such as electrolyte composition and capillary coatings. Further, conditions required for native ESI-MS of (large) protein constructs, including instrumental parameters of QTOF and Orbitrap systems, as well as requirements for native CE-MS interfacing are presented. On this basis, methods and applications of the different modes of native CE-MS are summarized and discussed in the context of biological, medical, and biopharmaceutical questions. Finally, key achievements are highlighted and concluded, while remaining challenges are pointed out.
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Affiliation(s)
| | - Lena Kruse
- Department of Chemistry, Aalen University, Aalen, Germany
| | - Kevin Jooß
- Department of Chemistry and Molecular Biosciences, the Chemistry of Life Processes Institute, and the Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, USA
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
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3
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Atia MA, Smejkal P, Gupta V, Haddad PR, Breadmore MC. Chemical vapour deposition in narrow capillaries: Electro-osmotic flow control in capillary electrophoresis. Anal Chim Acta 2023; 1280:341847. [PMID: 37858546 DOI: 10.1016/j.aca.2023.341847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/05/2023] [Accepted: 09/23/2023] [Indexed: 10/21/2023]
Abstract
BACKGROUND In capillary electrophoresis (CE), the inner surface of fused-silica capillaries is commonly covalently modified with liquid silanes to control electroosmotic flow (EOF). This liquid phase deposition (LPD) approach is challenging for long and narrow-diameter capillaries (≥1 m, ≤25 μm ID) inhibiting commercial production. Here, we use chemical vapour deposition (CVD) to covalently modify capillaries with different silanes. Using a home-built CVD device, capillaries were modified with neutral (3-glycidyloxypropyl) trimethoxysilane (GPTMS), the weak base (3-aminopropyl) trimethoxysilane (APTMS), the weak acid 3-mercaptopropyltrimethoxysilane (MPTMS) and the neutral hydrophobic trichloro(1H,1H,2H,2H-perfluorooctyl) silane (PFOCTS). Gas-phase modification of GPTMS with acid and ammonia allowed further modification of the surface prior to molecular layer deposition (MLD) of poly(p-phenylene terephthalamide) (PPTA) using the self-limiting sequential reaction between terephthalaldehyde (TA) and p-phenylenediamine (PD) vapours. RESULTS Capillaries coated with GPTMS by CVD showed a greater reduction in EOF at all pH values than the conventional LPD. APTMS showed a reduction of the EOF at pH 9, with EOF reversal observed below pH 6. MPTMS provided a slightly lower EOF than an unmodified capillary at high pH, and a slightly higher EOF at lower pH. PFOCTS provided the most consistent EOF as a function of pH. The deposition of successive layers of PPTA resulted in increased surface coverage of the polymer and a greater reduction in EOF at pH higher than 5. The stability of a 10 μm ID GPTMS coated capillary was tested at pH 8.8 in a 200 mM CHES/Tris BGE for the separation of inorganic anions. Over 1.5 months of continuous operation (≈4130 runs), the reproducibility of the apparent mobilities for chloride, nitrite, nitrate and sulfate were 2.43%, 2.56%, 2.63% and 3.05%, respectively. The intra-day and inter-day column-to-column reproducibility and batch-to-batch reproducibility for all the coated capillaries ranged between 0.34% and 3.95%. SIGNIFICANCE The study demonstrates the superior performance of CVD coating for suppressing the EOF compared to LPD allowing the easy modification of long lengths of narrow capillary. The variation in silane, and the ability of MLD to modify and control the surface chemistry, provides a simple and facile method for surface modification. The stability of these coatings will allow long-term capillary electrophoresis monitoring of water chemistry, such as for monitoring fertiliser run-off in natural waters.
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Affiliation(s)
- Mostafa A Atia
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania, 7001, Australia; Department of Analytical Chemistry, Faculty of Pharmacy Helwan University, 11795, Cairo, Egypt.
| | - Petr Smejkal
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania, 7001, Australia.
| | - Vipul Gupta
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania, 7001, Australia.
| | - Paul R Haddad
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania, 7001, Australia.
| | - Michael C Breadmore
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences, University of Tasmania, Private Bag 75, Hobart, Tasmania, 7001, Australia.
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4
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Stutz H. Advances and applications of electromigration methods in the analysis of therapeutic and diagnostic recombinant proteins – A Review. J Pharm Biomed Anal 2022; 222:115089. [DOI: 10.1016/j.jpba.2022.115089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 11/29/2022]
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Roca S, Dhellemmes L, Leclercq L, Cottet H. Polyelectrolyte Multilayers in Capillary Electrophoresis. Chempluschem 2022; 87:e202200028. [PMID: 35388990 DOI: 10.1002/cplu.202200028] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/19/2022] [Indexed: 02/21/2024]
Abstract
Capillary electrophoresis (CE) has been proven to be a performant analytical method to analyze both small and macro molecules. Indeed, it is capable of separating compounds of the same nature according to differences in their charge to size ratios, particularly proteins, monoclonal antibodies and peptides. However, one of the major obstacles to reach high separation efficiency remains the adsorption of solutes on the capillary wall. Among the different coating approaches used to control and minimize solute adsorption, polyelectrolyte multilayers can be applied to CE as a versatile approach. These coatings are made up of alternating layers of polycations and polyanions, and may be used in acidic, neutral or basic conditions depending on the solutes to be analyzed. This Review provides an overview of Successive Multiple Ionic-polymer Layer (SMIL) coatings used in CE, looking at how different parameters induce variations on the electro-osmotic flow (EOF), separation efficiency and coating stability, as well as their promising applications in the biopharmaceutical field.
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Affiliation(s)
- Sébastien Roca
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Laura Dhellemmes
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Laurent Leclercq
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Hervé Cottet
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
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6
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Yu RB, Quirino JP. Chiral separation using cyclodextrins as mobile phase additives in open-tubular liquid chromatography with a pseudophase coating. J Sep Sci 2022; 45:1195-1201. [PMID: 35014193 PMCID: PMC9304321 DOI: 10.1002/jssc.202100835] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 11/22/2022]
Abstract
The chiral separation of various analytes (dichlorprop, mecoprop, ibuprofen, and ketoprofen) was demonstrated with different cyclodextrins as mobile phase additives in open-tubular liquid chromatography using a stationary pseudophase semipermanent coating. The stable coating was prepared by a successive multiple ionic layer approach using poly(diallyldimethylammonium chloride), polystyrene sulfonate, and didodecyldimethyl ammonium bromide. Increasing concentrations (0-0.2 mM) of various native and derivatized cyclodextrins in 25 mM sodium tetraborate (pH 9.2) were investigated. Chiral separation was achieved for the four test analytes using 0.05-0.1 mM β-cyclodextrin (resolution between 1.11 and 1.34), γ-cyclodextrin (resolution between 0.78 and 1.27), carboxymethyl-β-cyclodextrin (resolution between 1.64 and 2.59), and 2-hydroxypropyl-β-cyclodextrin (resolution between 0.71 and 1.76) with the highest resolutions obtained with 0.1 mM carboxymethyl-β-cyclodextrin. %RSD values were <10%. This is the first demonstration of chiral open-tubular liquid chromatography using achiral chromatographic coatings and cyclodextrins as mobile phase additives.
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Affiliation(s)
- Raymond B. Yu
- Australian Centre for Research on Separation ScienceSchool of Natural Sciences‐ChemistryUniversity of TasmaniaHobartTasmaniaAustralia
| | - Joselito P. Quirino
- Australian Centre for Research on Separation ScienceSchool of Natural Sciences‐ChemistryUniversity of TasmaniaHobartTasmaniaAustralia
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7
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Salzer L, Stolz A, Dhellemmes L, Höchsmann A, Leclercq L, Cottet H, Neusüß C. Successive Multiple Ionic-Polymer Layer Coatings for Intact Protein Analysis by Capillary Zone Electrophoresis-Mass Spectrometry: Application to Hemoglobin Analysis. Methods Mol Biol 2022; 2531:69-76. [PMID: 35941479 DOI: 10.1007/978-1-0716-2493-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Adsorption of analytes, e.g., proteins, often interfere with separation in CE, due to the relatively large surface of the narrow capillary. Coatings often are applied to prevent adsorption and to determine the electroosmotic flow (EOF), which is of major importance for the separation in CE. Successive multiple ionic-polymer layer (SMIL) coatings are frequently used for protein analysis in capillary electrophoresis resulting in high separation efficiency and repeatability. Here, the coating procedure of a five-layer SMIL coating is described using quaternized diethylaminoethyl dextran (DEAEDq) as polycation and poly(methacrylic acid) (PMA) as polyanion. Depending on the analyte, different polyions may be used to increase separation efficiency. However, the coating procedure remains the same.To demonstrate the applicability of SMIL coatings in CE-MS, human hemoglobin was measured in a BGE containing 2 M acetic acid. DEAEDq-PMA coating was found to be the most suitable for hemoglobin analysis due to relatively low reversed electroosmotic mobility leading to increased electrophoretic resolution of closely related proteoforms. Thereby, not only alpha and beta subunit of the hemoglobin could be separated, but also positional isoforms of glycated and carbamylated species were separated within 24 min.
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Affiliation(s)
- Liesa Salzer
- Faculty of Chemistry, Aalen University, Aalen, Germany
- Analytical BioGeoChemistry (BGC), Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Laura Dhellemmes
- Institut des Biomolécules Max Mousseron, UMR CNRS, Université de Montpellier, Montpellier, France
| | | | - Laurent Leclercq
- Institut des Biomolécules Max Mousseron, UMR CNRS, Université de Montpellier, Montpellier, France
| | - Hervé Cottet
- Institut des Biomolécules Max Mousseron, UMR CNRS, Université de Montpellier, Montpellier, France
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8
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Hamidli N, Andrasi M, Nagy C, Gaspar A. Analysis of intact proteins with capillary zone electrophoresis coupled to mass spectromery using uncoated and coated capillaries. J Chromatogr A 2021; 1654:462448. [PMID: 34392123 DOI: 10.1016/j.chroma.2021.462448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/28/2021] [Accepted: 07/28/2021] [Indexed: 10/20/2022]
Abstract
Although, in general, the application of coated capillaries is recommended for the separation of intact proteins, bare silica capillary is still the most often used capillary due to its simplicity and cheapness. In this work, the performance of bare fused silica capillary for intact protein analysis was compared to that of different (dynamically coated polybrene (PB) and permanently coated linear polyacrylamide (LPA)) coated capillaries using capillary zone electrophoresis - mass spectrometry (CZE-MS). In cases where low pH (pH=1.8) was used in bare silica capillaries, good precision (0.56-0.78 RSD% and 1.7-6.5 RSD% for migration times and peak areas, respectively), minimal adsorption and separation efficiency (N= 27 000/m - 322 000/m) similar to or even better than those obtained with the coated capillaries (created by an intricate multi-step process) was achieved. The PB and the LPA capillaries demonstrated their slightly better resolving power in terms of separating the different forms/variants of the same protein (e.g., hemoglobin subunits). Among the studied capillaries the one with LPA coating showed the most stable separations in the long term (n=25: 0.18-0.49 RSD% and 3.1-4.9 RSD% for migration times and peak areas, respectively). For the separation of a few proteins or even a larger number of proteins in biological samples (e.g., snake venom) the application of the simple and cheap bare fused silica capillary can be considered as an efficient choice.
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Affiliation(s)
- N Hamidli
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, H-4032, Debrecen, Hungary
| | - M Andrasi
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, H-4032, Debrecen, Hungary
| | - C Nagy
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, H-4032, Debrecen, Hungary
| | - A Gaspar
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, H-4032, Debrecen, Hungary.
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9
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Villemet L, Cuchet A, Desvignes C, Sänger-van de Griend CE. Protein mapping of peanut extract with capillary electrophoresis. Electrophoresis 2021; 43:1027-1034. [PMID: 33970506 DOI: 10.1002/elps.202100004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/29/2021] [Accepted: 04/29/2021] [Indexed: 11/07/2022]
Abstract
Protein separation can be achieved with different modes of capillary electrophoresis, such as with capillary gel electroporesis (CGE) or with capillary zone electrophoresis (CZE). CZE protein mapping of peanut extract was approached in four different ways, combining neutral-coated or multilayer-coated capillaries with pHs well over or under the isoelectric point range of the proteins of interest. At acidic pHs, the mobility ranges of the major peanut allergens Ara h1, Ara h2, Ara h3, and Ara h6 were identified. Although the pH is a major factor in CZE separation, buffers with different compositions but with the same pH and ionic strength showed significantly different resolutions. Different components of the electrolyte were studied in a multifactorial design of experiment. CE-SDS and CZE proved to be suitable for protein mapping and we were able to distinguish different batches of peanut extract and burned peanut extract.
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Affiliation(s)
| | | | | | - Cari E Sänger-van de Griend
- Kantisto BV, Baarn, The Netherlands.,Faculty of Pharmacy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
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10
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HPLC Separation of Phenolic Acids on Silica Gels Layer-by-Layer Modified with 6,10-Ionene and Dextran Sulfate. J CHEM-NY 2020. [DOI: 10.1155/2020/5702940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Using phenolic acids as an example, we continue to study the nature of the previously obtained multilayer sorbents for HPLC—silica gels modified up to two times with 6,10-ionene and dextran sulfate (DS). The chromatographic behavior of this class of compounds on the obtained sorbents was studied. A six-component mixture of sorbic, vanillic, sinapic,
-coumaric, caffeic, and ferulic acids was separated on the silica gel twice modified with 6,10-ionene and dextran sulfate in 15 min with a selectivity of up to 1.88 and a column efficiency of up to 26000 theoretical plates per meter. The possibility of separating the two classes of compounds—phenolic acids and basic nitrogen-containing pharmaceuticals—in a single mixture on silica gel, twice modified with 6,10-ionene and dextran sulfate, is shown.
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11
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Leclercq L, Renard C, Martin M, Cottet H. Quantification of Adsorption and Optimization of Separation of Proteins in Capillary Electrophoresis. Anal Chem 2020; 92:10743-10750. [DOI: 10.1021/acs.analchem.0c02012] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Laurent Leclercq
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier 34095, France
| | - Charly Renard
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier 34095, France
| | - Michel Martin
- PMMH, CNRS, ESPCI Paris − PSL, Sorbonne Université, Université de Paris, Paris 75005, France
| | - Hervé Cottet
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier 34095, France
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12
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Zhang H, Lou C, Li J, Kang J. A gold foil covered fused silica capillary tip as a sheathless interface for coupling capillary electrophoresis-mass spectrometry. J Chromatogr A 2020; 1624:461215. [PMID: 32540065 DOI: 10.1016/j.chroma.2020.461215] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 12/19/2022]
Abstract
A method for the preparation of an on-column ESI emitter used as the sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry (MS) was developed. The emitter was directly fabricated at the outlet end of the separation capillary which was etched with HF solution to a symmetrical tip. The tip was covered with a small piece of gold foil which was fixed by epoxy resin glue for electrical contact. Such a prepared ESI emitter can produce a stable ESI signal over the wide range of flow rate from 50 nL/min to 800 nL/min. The performance of the CE-MS with the sheathless interface was evaluated by using the separation of four alkaloids. It was found that the strong electroosmotic flow produced by the multiple polyelectrolyte coating on the capillary is necessary for maintaining a stable MS signal. Effect of the running buffer composition, concentration and the CE separation voltages on the ESI signal strength were investigated. The absolute detection limits for the alkaloids was determined as fmol level. Moreover, the CE-MS was applied for the analyses of trypsin digestion of cytochrome C and small molecular organic anions. The emitter performed very stable with a lifetime of at least 180 h.
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Affiliation(s)
- Hanzhi Zhang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China; Shanghai Institute for Food and Drug Control, Zhangheng Road 1500, Shanghai 201203, China
| | - Chunli Lou
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China; School of Physical Science and Technology, ShanghaiTech University, Haike Road 100, Shanghai 200120, China
| | - Jing Li
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China; School of Physical Science and Technology, ShanghaiTech University, Haike Road 100, Shanghai 200120, China
| | - Jingwu Kang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China; School of Physical Science and Technology, ShanghaiTech University, Haike Road 100, Shanghai 200120, China.
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Leclercq L, Morvan M, Koch J, Neusüß C, Cottet H. Modulation of the electroosmotic mobility using polyelectrolyte multilayer coatings for protein analysis by capillary electrophoresis. Anal Chim Acta 2019; 1057:152-161. [DOI: 10.1016/j.aca.2019.01.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/17/2018] [Accepted: 01/04/2019] [Indexed: 12/26/2022]
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14
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Determination of neutral diols and carboxylic acids formed during glycerol electrooxidation by capillary electrophoresis with dual C4D. Talanta 2018; 178:1040-1045. [DOI: 10.1016/j.talanta.2017.08.088] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 11/27/2022]
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15
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Švidrnoch M, Boráňová B, Tomková J, Ondra P, Maier V. Simultaneous determination of designer benzodiazepines in human serum using non-aqueous capillary electrophoresis – Tandem mass spectrometry with successive multiple ionic – Polymer layer coated capillary. Talanta 2018; 176:69-76. [DOI: 10.1016/j.talanta.2017.08.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 07/30/2017] [Accepted: 08/02/2017] [Indexed: 01/07/2023]
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16
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Ioutsi AN, Shapovalova EN, Ioutsi VA, Mazhuga AG, Shpigun OA. Separation of pharmacologically active nitrogen-containing compounds on silica gels modified with 6,10-ionene, dextran sulfate, and gold nanoparticles. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2017. [DOI: 10.1134/s0036024417120111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Caslavska J, Thormann W. Monitoring of transferrin isoforms in biological samples by capillary electrophoresis. J Sep Sci 2017; 41:303-322. [PMID: 28885776 DOI: 10.1002/jssc.201700914] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/04/2017] [Accepted: 09/04/2017] [Indexed: 11/10/2022]
Abstract
Work dealing with the monitoring of transferrin isoforms in human serum and other body fluids by capillary electrophoresis is reviewed. It comprises capillary zone electrophoresis and capillary isoelectric focusing efforts that led to the exploration and use of assays for the determination of carbohydrate-deficient transferrin as a marker for excessive alcohol intake, genetic variants of transferrin, congenital disorders of glycosylation and β-2-transferrin, which is a marker for cerebrospinal fluid leakage. This paper provides insight into the development, specifications, strengths, weaknesses, and routine use of the currently known capillary electrophoresis based assays suitable to detect transferrin isoforms in body fluids. The achievements reached so far indicate that capillary zone electrophoresis is an attractive technology to monitor the molecular forms of transferrin in biological specimens as the assays do not require an elaborate sample pretreatment and thus can be fully automated for high-throughput analyses on multicapillary instruments. Assays based on capillary isoelectric focusing are less attractive. They require immunoextraction of transferrin from the biological matrix and mobilization after focusing if instrumentation with a whole-column imaging detector is not available. Interactions of the carrier ampholytes with the iron of transferrin may prevent iron saturation and thus provide more complicated isoform patterns.
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Affiliation(s)
- Jitka Caslavska
- Clinical Pharmacology Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Wolfgang Thormann
- Clinical Pharmacology Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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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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19
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Stock LG, Leitner M, Traxler L, Bonazza K, Leclercq L, Cottet H, Friedbacher G, Ebner A, Stutz H. Advanced portrayal of SMIL coating by allying CZE performance with in-capillary topographic and charge-related surface characterization. Anal Chim Acta 2017; 951:1-15. [DOI: 10.1016/j.aca.2016.10.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 10/22/2016] [Indexed: 10/20/2022]
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20
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Kowalski P, Olędzka I, Plenis A, Bączek T. Dynamic double coating, electrophoretic method with indirect detection for the simultaneous quantification of mono- and divalent cations in various water samples. Electrophoresis 2016; 38:477-485. [DOI: 10.1002/elps.201600205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 09/28/2016] [Accepted: 10/03/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Piotr Kowalski
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Gdańsk Poland
| | - Ilona Olędzka
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Gdańsk Poland
| | - Alina Plenis
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Gdańsk Poland
| | - Tomasz Bączek
- Department of Pharmaceutical Chemistry; Medical University of Gdańsk; Gdańsk Poland
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Tůmová T, Monincová L, Čeřovský V, Kašička V. Estimation of acidity constants, ionic mobilities and charges of antimicrobial peptides by capillary electrophoresis. Electrophoresis 2016; 37:3186-3195. [DOI: 10.1002/elps.201600342] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 08/25/2016] [Accepted: 09/18/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Tereza Tůmová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences; Prague Czech Republic
- Faculty of Food and Biochemical Technology; University of Chemistry and Technology Prague; Prague Czech Republic
| | - Lenka Monincová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences; Prague Czech Republic
| | - Václav Čeřovský
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences; Prague Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences; Prague Czech Republic
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22
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Leitner M, Stock LG, Traxler L, Leclercq L, Bonazza K, Friedbacher G, Cottet H, Stutz H, Ebner A. Mapping molecular adhesion sites inside SMIL coated capillaries using atomic force microscopy recognition imaging. Anal Chim Acta 2016; 930:39-48. [PMID: 27265903 DOI: 10.1016/j.aca.2016.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 04/29/2016] [Accepted: 05/01/2016] [Indexed: 10/21/2022]
Abstract
Capillary zone electrophoresis (CZE) is a powerful analytical technique for fast and efficient separation of different analytes ranging from small inorganic ions to large proteins. However electrophoretic resolution significantly depends on the coating of the inner capillary surface. High technical efforts like Successive Multiple Ionic Polymer Layer (SMIL) generation have been taken to develop stable coatings with switchable surface charges fulfilling the requirements needed for optimal separation. Although the performance can be easily proven in normalized test runs, characterization of the coating itself remains challenging. Atomic force microscopy (AFM) allows for topographical investigation of biological and analytical relevant surfaces with nanometer resolution and yields information about the surface roughness and homogeneity. Upgrading the scanning tip to a molecular biosensor by adhesive molecules (like partly inverted charged molecules) allows for performing topography and recognition imaging (TREC). As a result, simultaneously acquired sample topography and adhesion maps can be recorded. We optimized this technique for electrophoresis capillaries and investigated the charge distribution of differently composed and treated SMIL coatings. By using the positively charged protein avidin as a single molecule sensor, we compared these SMIL coatings with respect to negative charges, resulting in adhesion maps with nanometer resolution. The capability of TREC as a functional investigation technique at the nanoscale was successfully demonstrated.
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Affiliation(s)
- Michael Leitner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Lorenz G Stock
- Division of Chemistry and Bioanalytics, Department of Molecular Biology, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria; Christian Doppler Laboratory for Innovative Tools for the Characterization of Biosimilars, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria
| | - Lukas Traxler
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Laurent Leclercq
- Institut des Biomolécules Max Mousseron (IBMM, UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier), Place Eugène Bataillon, CC 1706, 34095 Montpellier, France
| | - Klaus Bonazza
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164, 1060 Vienna, Austria
| | - Gernot Friedbacher
- Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164, 1060 Vienna, Austria
| | - Hervé Cottet
- Institut des Biomolécules Max Mousseron (IBMM, UMR 5247, CNRS, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier), Place Eugène Bataillon, CC 1706, 34095 Montpellier, France
| | - Hanno Stutz
- Division of Chemistry and Bioanalytics, Department of Molecular Biology, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria; Christian Doppler Laboratory for Innovative Tools for the Characterization of Biosimilars, University Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria
| | - Andreas Ebner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria.
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23
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Wuethrich A, Haddad PR, Quirino JP. Field-enhanced sample injection micelle-to-solvent stacking capillary zone electrophoresis-electrospray ionization mass spectrometry of antibiotics in seawater after solid-phase extraction. Electrophoresis 2016; 37:1139-42. [DOI: 10.1002/elps.201500448] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/06/2016] [Accepted: 01/06/2016] [Indexed: 01/03/2023]
Affiliation(s)
- Alain Wuethrich
- Australian Centre for Research on Separation Science, School of Physical Sciences-Chemistry; University of Tasmania; Tasmania Australia
| | - Paul R. Haddad
- Australian Centre for Research on Separation Science, School of Physical Sciences-Chemistry; University of Tasmania; Tasmania Australia
| | - Joselito P. Quirino
- Australian Centre for Research on Separation Science, School of Physical Sciences-Chemistry; University of Tasmania; Tasmania Australia
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24
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Bekri S, Leclercq L, Cottet H. Polyelectrolyte multilayer coatings for the separation of proteins by capillary electrophoresis: Influence of polyelectrolyte nature and multilayer crosslinking. J Chromatogr A 2015; 1399:80-7. [DOI: 10.1016/j.chroma.2015.04.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/17/2015] [Accepted: 04/20/2015] [Indexed: 10/23/2022]
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Mádr A, Celá A, Klejdus B, Pelcová M, Crha I, Žáková J, Glatz Z. Determination of pyruvate and lactate as potential biomarkers of embryo viability in assisted reproduction by capillary electrophoresis with contactless conductivity detection. Electrophoresis 2015; 36:1244-50. [PMID: 25639526 DOI: 10.1002/elps.201400487] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/19/2014] [Accepted: 12/22/2014] [Indexed: 01/06/2023]
Abstract
Human-assisted reproduction is increasing in importance due to the constantly rising number of couples suffering from infertility issue. A key step in in vitro fertilization is the proper assessment of embryo viability in order to select the embryo with the highest likelihood of resulting in a pregnancy. This study proposes a method based on CE with contactless conductivity detection for the determination of pyruvate and lactate in spent culture media used in human-assisted reproduction. A fused-silica capillary of 64.0 cm total length and 50 μm inner diameter was used. The inner capillary wall was modified by the coating of successive layers of the ionic polymers polybrene and dextran sulfate to reverse EOF. The BGE was composed of 10 mM MES/lithium hydroxide, pH 6.50. The sample was injected by pressure 50 mbar for 18 s, separation voltage was set to -24 kV, and capillary temperature to 15°C. The presented method requires only 2 μL of the culture medium, with LODs for pyruvate and lactate of 0.03 and 0.02 μM, respectively. The results demonstrated the method's suitability for the analysis of spent culture media to support embryo viability assessment by light microscopy, providing information about key metabolites of the energy metabolism of a developing embryo.
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Affiliation(s)
- Aleš Mádr
- Department of Biochemistry, Faculty of Science and CEITEC, Masaryk University, Brno, Czech Republic
| | - Andrea Celá
- Department of Biochemistry, Faculty of Science and CEITEC, Masaryk University, Brno, Czech Republic
| | - Bořivoj Klejdus
- Department of Biochemistry, Faculty of Science and CEITEC, Masaryk University, Brno, Czech Republic
| | - Marta Pelcová
- Department of Biochemistry, Faculty of Science and CEITEC, Masaryk University, Brno, Czech Republic
| | - Igor Crha
- Department of Obstetrics and Gynecology, Faculty of Medicine, Masaryk University and University Hospital Brno, Brno, Czech Republic
| | - Jana Žáková
- Department of Obstetrics and Gynecology, Faculty of Medicine, Masaryk University and University Hospital Brno, Brno, Czech Republic
| | - Zdeněk Glatz
- Department of Biochemistry, Faculty of Science and CEITEC, Masaryk University, Brno, Czech Republic
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26
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Layer-by-Layer Assembly of Polysaccharides and 6,10-Ionene for Separation of Nitrogen-Containing Pharmaceuticals and Their Enantiorecognition by Capillary Electrophoresis. J CHEM-NY 2015. [DOI: 10.1155/2015/836076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Two silica capillaries modified layer-by-layer with 6,10-ionene and N-(3-sulfo-3-carboxy)-propionylchitosan (SCPC) and with 6,10-ionene and dextran sulfate (DS) were prepared and investigated. Dynamic coating of the capillary efficiently reduces the adsorption of the background electrolyte, sample matrix components, and analytes on its inner wall. Such coatings effect good reproducibility and sensitivity of determination. We demonstrate that separation of betablockers, calcium channel blockers, alpha-adrenergic agonists, H1-blockers, and diuretics was the most efficient and rapid separation with a capillary modified with dextran sulfate. Tetrahydrozoline, carbinoxamine, and furacilin, which are commonly employed as treatments for allergic rhinitis, were identified in human urea. Their concentrations, independently verified by HPLC, were found to be5.3±0.8,6.6±0.5, and0.9±0.2 μg mL−1, withLOD=0.07, 0.03, 0.10 μg mL−1, andLOQ=1.0, 0.8, 0.6 μg mL−1, respectively.
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27
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Liu JX, Aerts JT, Rubakhin SS, Zhang XX, Sweedler JV. Analysis of endogenous nucleotides by single cell capillary electrophoresis-mass spectrometry. Analyst 2014; 139:5835-42. [PMID: 25212237 PMCID: PMC4329915 DOI: 10.1039/c4an01133c] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Analytical technologies that enable investigations at the single cell level facilitate a range of studies; here a lab-fabricated capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) platform was used to analyze anionic metabolites from individual Aplysia californica neurons. The system employs a customized coaxial sheath-flow nanospray interface connected to a separation capillary, with the sheath liquid and separation buffer optimized to ensure a stable spray. The method provided good repeatability of separation and reliable detection sensitivity for 16 mono-, di- and triphosphate nucleosides. For a range of anionic analytes, including cyclic adenosine monophosphate (cAMP), adenosine diphosphate (ADP) and adenosine triphosphate (ATP), the detection limits were in the low nanomolar range (<22 nM). A large Aplysia R2 neuron was used to demonstrate the ability of CE-ESI-MS to quantitatively characterize anionic metabolites within individual cells, with 15 nucleotides and derivatives detected. Following the method validation process, we probed smaller, 60 μm diameter Aplysia sensory neurons where sample stacking was used as a simple on-line analyte preconcentration approach. The calculated energy balance ([ATP] + 0.5 × [ADP])/([AMP] + [ADP] + [ATP]) of these cells was comparable with the value obtained from bulk samples.
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Affiliation(s)
- Jing-Xin Liu
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois,USA
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry, College of Chemistry, Peking University, Beijing, China
| | - Jordan T. Aerts
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois,USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois,USA
| | - Stanislav S. Rubakhin
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois,USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois,USA
| | - Xin-Xiang Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education; Institute of Analytical Chemistry, College of Chemistry, Peking University, Beijing, China
| | - Jonathan V. Sweedler
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois,USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois,USA
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28
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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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29
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Kok MG, Somsen GW, de Jong GJ. The role of capillary electrophoresis in metabolic profiling studies employing multiple analytical techniques. Trends Analyt Chem 2014. [DOI: 10.1016/j.trac.2014.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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30
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Insight into the stability of poly(diallydimethylammoniumchloride) and polybrene poly cationic coatings in capillary electrophoresis. J Chromatogr A 2014; 1365:226-33. [DOI: 10.1016/j.chroma.2014.09.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/03/2014] [Accepted: 09/05/2014] [Indexed: 12/16/2022]
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31
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Takahashi T, Kawana J, Tamura Y, Hoshino H. Dynamic coating capillary electrophoresis for separation of humic acid using mixture solution of non-ionic polymers both as coating agent and separation medium. ANAL SCI 2014; 29:1099-102. [PMID: 24212738 DOI: 10.2116/analsci.29.1099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A simple, rapid, and precise dynamic coating capillary electrophoretic separation method for water-soluble humic substances is proposed. An aqueous solution containing hydroxyethyl cellulose (HEC), polyethylene glycol (PEG), and pH buffer component was employed for both the dynamic coating agent and the separation medium. The procedure for the coating of the capillary inner wall was simply filling the buffered polymer mixture solution into the capillary that had been treated with 1 M aqueous HCl solution. The solution for the capillary coating was directly used as the electrophoretic buffer solution for CE separation. Excellent performance for the separation of humic acid was obtained using the solution containing 0.5% (w/v) HEC, 1.0% (w/v) PEG 10000, and 0.1% (w/v) PEG 8000000. Excellent reproducibility and durability were obtained even at slightly alkaline conditions at pH levels above 8. The separation of 0.1 - 2 kbp of DNA ladder by the proposed method showed was also achieved.
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Rogez-Florent T, Foulon C, Six P, Goossens L, Danel C, Goossens JF. Optimization of the enantioseparation of a diaryl-pyrazole sulfonamide derivative by capillary electrophoresis in a dual CD mode using experimental design. Electrophoresis 2014; 35:2765-71. [PMID: 24723380 DOI: 10.1002/elps.201300639] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/27/2014] [Accepted: 03/29/2014] [Indexed: 11/11/2022]
Abstract
A CE method using dual cationic and neutral cyclodextrins (CD) was optimized for the enantiomeric separation of a compound presenting a diaryl sulfonamide group. Preliminary studies were made to select the optimal CDs and pH of the BGE. Two CDs (amino-β-CD and β-CD) were selected to separate the enantiomers in a 67 mM phosphate buffer at pH 7.4. However, the repeatability of the analyses obtained on bare-fused silica capillary was not acceptable owing to the adsorption of the amino-β-CD to the capillary. To prevent this, a dynamic coating of the capillary was used employing five layers of ionic-polymer (poly(diallyldimethylammonium) chloride (PDADMAC) and poly(sodium 4-styrenesulfonate). The efficiency of the coating was assessed by measuring the EOF stability. Repeatability of the injections was obtained when intermediate coating with PDADMAC was performed between each run. Secondly, this enantioseparation method was optimized using a central composite circumscribed design including three factors: amino-β-CD and β-CD concentrations and the percentage of methanol. Under the optimal conditions (i.e. 16.6 mM of amino-β-CD, 2.6 mM of β-CD, 0% MeOH in 67 mM phosphate buffer (pH 7.4) as BGE, cathodic injection 0.5 psi, 5 s, separation voltage 15 kV and a temperature of 15°C), complete enantioresolution of the analyte was obtained. It is worth mentioning that the design of experiments (DOE) protocol employed showed a significant interaction between CDs, highlighting the utility of DOE in method development. Finally, small variations in the ionic-polymer concentrations did not significantly influence the EOF, confirming the robustness of the coating method.
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Affiliation(s)
- Tiphaine Rogez-Florent
- Université Lille Nord de France, Lille, France; UDSL, Analytics chemistry laboratory, Lille, France
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Vitali L, Della Betta F, Costa ACO, Vaz FAS, Oliveira MAL, Pereira Vistuba J, Fávere VT, Micke GA. New multilayer coating using quaternary ammonium chitosan and κ-carrageenan in capillary electrophoresis: Application in fast analysis of betaine and methionine. Talanta 2014; 123:45-53. [DOI: 10.1016/j.talanta.2014.01.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/17/2014] [Accepted: 01/20/2014] [Indexed: 10/25/2022]
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34
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Tubaon RM, Haddad PR, Quirino JP. High-sensitivity analysis of anionic sulfonamides by capillary electrophoresis using a synergistic stacking approach. J Chromatogr A 2014; 1349:129-34. [PMID: 24856966 DOI: 10.1016/j.chroma.2014.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/19/2014] [Accepted: 05/02/2014] [Indexed: 11/19/2022]
Abstract
A synergistic stacking approach whereby field-enhanced sample injection and micelle-to-solvent stacking in capillary zone electrophoresis are combined has been developed and has been applied to the separation and quantification of anionic sulfonamides. Electrokinetic injection of the sample in a low conductivity alkaline diluent was performed for 90s at -15kV. Micelle-to-solvent stacking was then undertaken by hydrodynamic injection of micellar cetyltrimethylammonium bromide solution prior to the electrokinetic injection of sample that also contained 50% methanol. This combined stacking approach, when compared to a typical hydrostatic injection, provided improvements in peak height and corrected peak area in the range of 397-1024 and 758-1246, respectively. Limits of quantification in the range of 0.01-0.03μg/mL were obtained for sulfamerazine, sulfamethazine and sulfamethizole and were sufficient for the determination of these analytes in river water. The percentage recovery and accuracy values obtained for a fortified river water sample that had been subjected to sample preparation by evaporation and reconstitution with diluent were 74-135%. Intra-day and inter-day repeatabilities for migration time, peak height, and corrected peak area were in the range 0.5-5.0% (percentage relative standard deviation, n=8) and these relatively low values were attributed to the use of a stable capillary coating established by the successive multiple ionic-polymer layer technique.
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Affiliation(s)
- Ria Marni Tubaon
- Australian Centre for Research on Separation Science, School of Physical Sciences-Chemistry, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Paul R Haddad
- Australian Centre for Research on Separation Science, School of Physical Sciences-Chemistry, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Joselito P Quirino
- Australian Centre for Research on Separation Science, School of Physical Sciences-Chemistry, University of Tasmania, Hobart, Tasmania 7001, Australia.
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35
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Currie CA, Woods CD, Stanley FE, Stalcup AM. CHIRAL SEPARATIONS USING HEPARIN AND POLYELECTROLYTE MULTILAYERS IN CAPILLARY ELECTROPHORESIS. J LIQ CHROMATOGR R T 2014. [DOI: 10.1080/10826076.2013.830266] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- C. A. Currie
- a Department of Chemistry , College of Mount St. Joseph , Cincinnati , Ohio , USA
| | - C. D. Woods
- a Department of Chemistry , College of Mount St. Joseph , Cincinnati , Ohio , USA
| | - F. E. Stanley
- b Department of Chemistry , University of Cincinnati , Cincinnati , Ohio , USA
| | - A. M. Stalcup
- b Department of Chemistry , University of Cincinnati , Cincinnati , Ohio , USA
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36
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Stereospecific electrophoretically mediated microanalysis assay for methionine sulfoxide reductase enzymes. Anal Bioanal Chem 2014; 406:1723-9. [DOI: 10.1007/s00216-013-7596-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 12/14/2013] [Accepted: 12/19/2013] [Indexed: 12/19/2022]
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37
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Wuethrich A, Haddad PR, Quirino JP. Zero net-flow in capillary electrophoresis using acrylamide based hydrogel. Analyst 2014; 139:3722-6. [DOI: 10.1039/c4an00557k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Zero net-flow was observed when acrylamide based hydrogel was used in a vial at one end of a fused-silica capillary during electrophoresis with electroosmotic flow.
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Affiliation(s)
- Alain Wuethrich
- Australian Centre for Research on Separation Science (ACROSS)
- School of Physical Sciences-Chemistry
- University of Tasmania
- Hobart, Australia
| | - Paul R. Haddad
- Australian Centre for Research on Separation Science (ACROSS)
- School of Physical Sciences-Chemistry
- University of Tasmania
- Hobart, Australia
| | - Joselito P. Quirino
- Australian Centre for Research on Separation Science (ACROSS)
- School of Physical Sciences-Chemistry
- University of Tasmania
- Hobart, Australia
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38
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Zhu Q, El-Mergawy RG, Heinemann SH, Schönherr R, Jáč P, Scriba GKE. Stereospecific micellar electrokinetic chromatography assay of methionine sulfoxide reductase activity employing a multiple layer coated capillary. Electrophoresis 2013; 34:2712-7. [DOI: 10.1002/elps.201300147] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 04/18/2013] [Accepted: 04/20/2013] [Indexed: 12/13/2022]
Affiliation(s)
- Qingfu Zhu
- Department of Pharmaceutical Chemistry; Friedrich Schiller University Jena; Jena; Germany
| | - Rabab G. El-Mergawy
- Department of Biophysics; Friedrich Schiller University Jena and Jena University Hospital; Jena; Germany
| | - Stefan H. Heinemann
- Department of Biophysics; Friedrich Schiller University Jena and Jena University Hospital; Jena; Germany
| | - Roland Schönherr
- Department of Biophysics; Friedrich Schiller University Jena and Jena University Hospital; Jena; Germany
| | - Pavel Jáč
- Department of Pharmaceutical Chemistry; Friedrich Schiller University Jena; Jena; Germany
| | - Gerhard K. E. Scriba
- Department of Pharmaceutical Chemistry; Friedrich Schiller University Jena; Jena; Germany
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Liu JX, Zhao MZ, Deng Y, Tie C, Chen HX, Zhou YL, Zhang XX. The coating of smart pH-responsive polyelectrolyte brushes in capillary and its application in CE. Electrophoresis 2013; 34:1352-8. [PMID: 23436557 DOI: 10.1002/elps.201200518] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 01/02/2013] [Accepted: 01/10/2013] [Indexed: 11/07/2022]
Abstract
A novel pH-responsive coating technique was developed and applied to CE successfully in this paper. The coating was formed by bonding mixed opposite charge poly(acrylic acid) and poly(2-vinylpyridine) randomly onto the inner wall of a silica capillary. The coating processes were first characterized by ellipsometry and atomic force microscopy at macroscale and microscale, respectively. Measurements of EOF were implemented to confirm the coating. Direction and velocity of EOF became controllable from negative to positive, showing a perfect sigmoidal curve as the coating net charges alternated by the pH of BGE. The control of the EOF makes it possible to analyze different kinds of small molecules, peptides, and proteins successfully in the same capillary. Results showed that the stability and reproducibility for separations of fluoroquinolone standards were satisfactory for more than a hundred separations. A series of basic and acidic protein standards were separated with admirable efficiency and minimal adsorption using both polarities. The separation of tryptic BSA digest showed that the prepared capillary has immense potential in analyzing a single sample with both acidic and basic separations, which achieved the expectation in proteomics study by CE-MS.
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Affiliation(s)
- Jing-Xin Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry, Peking University, Beijing, PR China
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40
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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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41
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Sarazin C, Delaunay N, Costanza C, Eudes V, Gareil P. On the use of capillary electrophoresis for the determination of inorganic anions and cations, and carbohydrates in residues collected after a simulated suicide bombing attack. Talanta 2013. [DOI: 10.1016/j.talanta.2012.10.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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42
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Affiliation(s)
- Jitka Caslavska
- Clinical Pharmacology Laboratory; Institute for Infectious Diseases; University of Bern; Bern; Switzerland
| | - Wolfgang Thormann
- Clinical Pharmacology Laboratory; Institute for Infectious Diseases; University of Bern; Bern; Switzerland
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43
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Guan Q, Noblitt SD, Henry CS. Electrophoretic separations in poly(dimethylsiloxane) microchips using mixtures of ionic, nonionic and zwitterionic surfactants. Electrophoresis 2012; 33:2875-83. [PMID: 23019105 PMCID: PMC3804416 DOI: 10.1002/elps.201200255] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The use of surfactant mixtures to affect both EOF and separation selectivity in electrophoresis with PDMS substrates is reported, and capacitively coupled contactless conductivity detection is introduced for EOF measurement on PDMS microchips. First, the EOF was measured for two nonionic surfactants (Tween 20 and Triton X-100), mixed ionic/nonionic surfactant systems (SDS/Tween 20 and SDS/Triton X-100), and finally for the first time, mixed zwitterionic/nonionic surfactant systems (TDAPS/Tween 20 and TDAPS/Triton X-100). EOF for the nonionic surfactants decreased with increasing surfactant concentration. The addition of SDS or TDAPS to a nonionic surfactant increased EOF. After establishing the EOF behavior, the separation of model catecholamines was explored to show the impact on separations. Similar analyte resolution with greater peak heights was achieved with mixed surfactant systems containing Tween 20 and TDAPS relative to the single surfactant system. Finally, the detection of catecholamine release from PC12 cells by stimulation with 80 mM K(+) was performed to demonstrate the usefulness of mixed surfactant systems to provide resolution of biological compounds in complex samples.
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Affiliation(s)
- Qian Guan
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
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44
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Zhou L, Reen FJ, O’Gara F, McSweeney CM, Clarke SL, Glennon JD, Luong JH, McGlacken GP. Analysis of pseudomonas quinolone signal and other bacterial signalling molecules using capillaries coated with highly charged polyelectrolyte monolayers and boron doped diamond electrode. J Chromatogr A 2012; 1251:169-175. [DOI: 10.1016/j.chroma.2012.06.064] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/18/2012] [Accepted: 06/19/2012] [Indexed: 01/30/2023]
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45
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Improved capillary electrophoresis frontal analysis by dynamically coating the capillary with polyelectrolyte multilayers. J Chromatogr A 2012; 1238:146-51. [DOI: 10.1016/j.chroma.2012.03.043] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/09/2012] [Accepted: 03/12/2012] [Indexed: 02/01/2023]
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46
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Braud C. Capillary zone electrophoresis as a tool to monitor the last stages of the degradation of water-sensitive polymers. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 15:423-47. [PMID: 15212327 DOI: 10.1163/156856204323005299] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In order to monitor the formation of the water-soluble by-products from chain-scission of degradable polymers used in the biomedical field, four capillary electrophoresis methods are discussed with the aim of giving the limits and performance for each. Three of them (electroosmotic flow reversal by dynamic adsorption of a polycation, multilayer polyelectrolyte coatings and physical binding of polyethylene oxide) are based on the use of dynamic coatings onto the inner surface of a fused silica capillary, a simple means to adapt performance to specific separations via modification and control of the electroosmotic flow of fused capillary. Using oligomers of lactic acid considered as standards the methods are compared. Other examples of ester-containing macromolecules (poly(hydroxybutyrate)), as well as degradable polyanions are described, namely N-acetylneuraminate polymer and poly(beta-malic acid).
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Affiliation(s)
- Christian Braud
- CRBA, CNRS, UMR 5473, Faculté de Pharmacie, Université Montpellier 1, 15 avenue Charles Flahault, BP 14491, 34093 Montpellier 5, France.
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47
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Guan Q, Noblitt SD, Henry CS. Electrophoretic separations in poly(dimethylsiloxane) microchips using a mixture of ionic and zwitterionic surfactants. Electrophoresis 2012; 33:379-87. [PMID: 22222982 PMCID: PMC3516918 DOI: 10.1002/elps.201100259] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The use of mixtures of ionic and zwitterionic surfactants in poly(dimethylsiloxane) (PDMS) microchips is reported. The effect of surfactant concentration on electroosmotic flow (EOF) was studied for a single anionic surfactant (sodium dodecyl sulfate, SDS), a single zwitterionic surfactant (N-tetradecylammonium-N,N-dimethyl-3-ammonio-1-propanesulfonate, TDAPS), and a mixed SDS/TDAPS surfactant system. SDS increased the EOF as reported previously while TDAPS showed an initial increase in EOF followed by a reduction at higher concentrations. When TDAPS was added to a solution containing SDS, the EOF decreased in a concentration-dependent manner. The EOF for all three surfactant systems followed expected pH trends, with increasing EOF at higher pH. The mixed surfactant system allowed tuning of the EOF across a range of pH and concentration conditions. After establishing the EOF behavior, the adsorption/desorption kinetics were measured and showed a slower adsorption/desorption rate for TDAPS than SDS. Finally, the separation and electrochemical detection of model catecholamines in buffer and reduced glutathione in red blood cell lysate using the mixed surfactant system were explored. The mixed surfactant system provided shorter analysis times and/or improved resolution when compared to the single surfactant systems.
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Affiliation(s)
- Qian Guan
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
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48
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Han Y, Bai Y, Xiao Y, Du F, Liang Y, Tan Z, Zhao M, Liu H. Simultaneous discrimination of jasmonic acid stereoisomers by CE-QTOF-MS employing the partial filling technique. Electrophoresis 2011; 32:2693-9. [PMID: 21910130 DOI: 10.1002/elps.201100043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 03/22/2011] [Accepted: 03/31/2011] [Indexed: 11/10/2022]
Abstract
Jasmonic acid (JA), an essential plant hormone controlling the plant defense signaling system and developmental processes, has stereospecific bioactivities that have not been well understood mainly due to the limitation in separation and detection methodologies. In this work, a fast CE-UV method based on short-end injection technique and a sensitive CE-QTOF-MS method based on partial filling technique were successfully developed for the enantioseparation of racemic JA. The successive coating technique was also involved by modifying the capillary with multiple ionic polymer layers of polybrene-dextran sulfate-polybrene. This was the first report on the direct resolution of both pairs of JA enantiomers, including two naturally occurring JA stereoisomers. Although no pure JA stereoisomers were commercially available, all the separated JA stereoisomers were identified indirectly by comparing the difference between the racemic standard and plant samples based on the presence and the ratio of each stereoisomer. Satisfactory results were obtained in terms of sensitivity (LOD, 24 ng/mL or 0.7 fmol for single JA stereoisomer) using 45 mmol/L ammonium acetate at pH 4.5 containing 70 mmol/L α-CD as the buffer system. This established CE-QTOF-MS method was later successfully applied for the study of the naturally occurring JA stereoisomers in wounded tobacco leaves.
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Affiliation(s)
- Yehua Han
- Beijing National Laboratory for Molecular Sciences, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, P. R. China
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Zhao J, Zhang Q, Yang H, Tu Y. Electrophoretic separation of neurotransmitters on a polystyrene nano-sphere∕polystyrene sulphonate coated poly(dimethylsiloxane) microchannel. BIOMICROFLUIDICS 2011; 5:34104-341049. [PMID: 21918677 PMCID: PMC3172124 DOI: 10.1063/1.3609968] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/17/2011] [Indexed: 05/31/2023]
Abstract
In this paper, a poly(dimethylsiloxane) microchip with amperometric detector was developed for the electrophoretic separation and determination of neurotransmitters. For increasing the separation efficiency, the microchannel is modified by polystyrene sulphonate∕polystyrene nano-sphere self-assembly coating. A stable electro-osmotic flow (EOF) and higher separation efficiency are obtained in proposed modified microchannel. Under optimized conditions, dopamine, epinephrine, catechol, and serotonin are acceptably baseline separated in this 3.5 cm length separation channel with the theoretical plate number from 4.6 × 10(4) to 2.1 × 10(5) per meter and resolution from 1.29 to 12.5. The practicability of proposed microchip is validated by the recovery test with cerebrospinal fluid as real sample which resulted from 91.7% to 106.5%.
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50
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Swords KE, Bartline PB, Roguski KM, Bashaw SA, Frederick KA. Assessment of polyelectrolyte coating stability under dynamic buffer conditions in CE. J Sep Sci 2011; 34:2427-32. [DOI: 10.1002/jssc.201100044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 05/26/2011] [Accepted: 06/01/2011] [Indexed: 11/05/2022]
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