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de Koster N, Clark CP, Kohler I. Past, present, and future developments in enantioselective analysis using capillary electromigration techniques. Electrophoresis 2021; 42:38-57. [PMID: 32914880 PMCID: PMC7821218 DOI: 10.1002/elps.202000151] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/22/2020] [Accepted: 09/08/2020] [Indexed: 12/16/2022]
Abstract
Enantioseparation of chiral products has become increasingly important in a large diversity of academic and industrial applications. The separation of chiral compounds is inherently challenging and thus requires a suitable analytical technique that can achieve high resolution and sensitivity. In this context, CE has shown remarkable results so far. Chiral CE offers an orthogonal enantioselectivity and is typically considered less costly than chromatographic techniques, since only minute amounts of chiral selectors are needed. Several CE approaches have been developed for chiral analysis, including chiral EKC and chiral CEC. Enantioseparations by EKC benefit from the wide variety of possible pseudostationary phases that can be employed. Chiral CEC, on the other hand, combines chromatographic separation principles with the bulk fluid movement of CE, benefitting from reduced band broadening as compared to pressure-driven systems. Although UV detection is conventionally used for these approaches, MS can also be considered. CE-MS represents a promising alternative due to the increased sensitivity and selectivity, enabling the chiral analysis of complex samples. The potential contamination of the MS ion source in EKC-MS can be overcome using partial-filling and counter-migration techniques. However, chiral analysis using monolithic and open-tubular CEC-MS awaits additional method validation and a dedicated commercial interface. Further efforts in chiral CE are expected toward the improvement of existing techniques, the development of novel pseudostationary phases, and establishing the use of chiral ionic liquids, molecular imprinted polymers, and metal-organic frameworks. These developments will certainly foster the adoption of CE(-MS) as a well-established technique in routine chiral analysis.
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Affiliation(s)
- Nicky de Koster
- Leiden Academic Centre for Drug Research, Division of Systems Biomedicine and PharmacologyLeiden UniversityLeidenThe Netherlands
| | - Charles P. Clark
- Leiden Academic Centre for Drug Research, Division of Systems Biomedicine and PharmacologyLeiden UniversityLeidenThe Netherlands
| | - Isabelle Kohler
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute for Molecular and Life SciencesVrije Universiteit AmsterdamAmsterdamThe Netherlands
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2
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Chiral Micellar Electrokinetic Chromatography. J Chromatogr A 2020; 1626:461383. [PMID: 32797856 DOI: 10.1016/j.chroma.2020.461383] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 12/18/2022]
Abstract
The potential of Micellar Electrokinetic Chromatography to achieve enantiomeric separations is reviewed in this article. The separation principles and the most frequently employed separation strategies to achieve chiral separations by Micellar Electrokinetic Chromatography are described. The use of chiral micellar systems alone or combined with other micellar systems or chiral selectors, as well as of mixtures of achiral micellar systems with chiral selectors is discussed together with the effect of different additives present in the separation medium. Indirect methods based on the derivatization of analytes with chiral derivatizing reagents and the use of achiral micelles are also considered. Preconcentration techniques employed to improve sensitivity and the main approaches developed to facilitate the coupling with Mass Spectrometry are included. The most recent and relevant methodologies developed by chiral Micellar Electrokinetic Chromatography and their applications in different fields are presented.
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3
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Patel V, Shamsi SA. Carbohydrate-Based Polymeric Surfactants for Chiral Micellar Electrokinetic Chromatography (CMEKC) Coupled to Mass Spectrometry. Methods Mol Biol 2019; 1985:417-444. [PMID: 31069750 PMCID: PMC7199777 DOI: 10.1007/978-1-4939-9438-0_25] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Polymeric surfactants (molecular micelles, MoMs) with a variety of chiral head groups and chain lengths may be the most promising chiral selectors when used for sensitive detection of chiral compounds in micellar electrokinetic chromatography-mass spectrometry (MEKC-MS). Various carbohydrate-based MS compatible surfactants with phosphate and sulfate head groups have been recently synthesized in our laboratory for its application in CMEKC-MS. In this chapter, we illustrate that the synthesized glucopyranoside-based MoMs are fully compatible with electrospray ionization MS and can be successfully used as a chiral selector for high-throughput screening of multiple chiral compounds using MRM mode in CMEKC-MS/MS experiments. This chapter describes in detail synthesis and utility of α- and β-glucopyranoside-based polymeric surfactant with two different chain lengths and head groups. The presented examples optimize the effect of appropriate millimolar concentration of monomer sugar surfactants required for polymerization as it affects the separations of acidic and basic compounds. Under the optimized concentration of the monomer needed for polymerization (i.e., an equivalent monomer concentration of MoMs), the superiority of MEKC-MS over MEKC-UV is evident. Structurally similar basic drugs with the difference in hydrophobicity are first tested in MEKC-MS to find the optimum head group and optimum chain length with the aim for developing a widely applicable polymeric glucopyranoside-based surfactant. The partial enantioresolution of several structurally similar basic compounds is significantly improved when switching from one head group to another head group of the glucopyranoside MoMs. Thus, complementary separations using poly-N-β-D-SUGP versus poly-N-β-D-SUGS were seen. This phenomenon also exists when comparing the MoMs, which differ in an anomeric configuration such as poly-N-α-D-SUGP and poly-N-β-D-SUGP.
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Affiliation(s)
- Vijay Patel
- Department of Chemistry, Georgia State University, Natural Science Center, Atlanta, GA, USA
| | - Shahab A Shamsi
- Department of Chemistry, Georgia State University, Natural Science Center, Atlanta, GA, USA.
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Prior A, Sánchez-Hernández L, Sastre-Toraño J, Marina ML, de Jong GJ, Somsen GW. Enantioselective analysis of proteinogenic amino acids in cerebrospinal fluid by capillary electrophoresis-mass spectrometry. Electrophoresis 2016; 37:2410-9. [PMID: 27465690 DOI: 10.1002/elps.201600015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/06/2016] [Accepted: 06/15/2016] [Indexed: 11/06/2022]
Abstract
d-Amino acids (AAs) are increasingly being recognized as essential molecules in biological systems. Enantioselective analysis of proteinogenic AAs in biological samples was accomplished by CE-MS employing β-CD as chiral selector and ESI via sheath-liquid (SL) interfacing. Prior to analysis, AAs were fully derivatized with FMOC, improving AA-enantiomer separation and ESI efficiency. In order to optimize the separation and MS detection of FMOC-AAs, the effects of type and concentration of CD in the BGE, the composition of the SL, and MS-interfacing parameters were evaluated. Using a BGE of 10 mM β-CD in 50 mM ammonium bicarbonate (pH 8) containing 15% v/v isopropanol, a SL of isopropanol-water-1 M ammonium bicarbonate (50:50:1, v/v/v) at a flow rate of 3 μL/min, and a nebulizer gas pressure of 2 psi, 15 proteinogenic AAs could be detected with enantioresolutions up to 3.5 and detection limits down to 0.9 μM (equivalent to less than 3 pg AA injected). The selectivity of the method was demonstrated by the analysis of spiked cerebrospinal fluid, allowing specific detection of d-AAs. Repeatability and linearity obtained for cerebrospinal fluid were similar to standard solutions, with peak area and migration-time RSDs (n = 5) below 16.2 and 1.6%, respectively, and a linear response (R(2) ≥ 0.977) in the 3-90 μM range.
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Affiliation(s)
- Amir Prior
- Division of BioAnalytical Chemistry, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| | - Laura Sánchez-Hernández
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Universidad de Alcalá, Alcalá de Henares (Madrid), Spain
| | - Javier Sastre-Toraño
- Division of Biomolecular Analysis, Utrecht University, CG Utrecht, The Netherlands
| | - Maria Luisa Marina
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Universidad de Alcalá, Alcalá de Henares (Madrid), Spain
| | - Gerhardus J de Jong
- Division of Biomolecular Analysis, Utrecht University, CG Utrecht, The Netherlands
| | - Govert W Somsen
- Division of BioAnalytical Chemistry, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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5
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Determination of selected synthetic cannabinoids and their metabolites by micellar electrokinetic chromatography – mass spectrometry employing perfluoroheptanoic acid-based micellar phase. Talanta 2016; 150:568-76. [DOI: 10.1016/j.talanta.2015.12.078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 12/27/2015] [Accepted: 12/30/2015] [Indexed: 11/22/2022]
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6
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Liu Y, Wu B, Wang P, Shamsi SA. Synthesis, characterization, and application of polysodium N-alkylenyl α-d-glucopyranoside surfactants for micellar electrokinetic chromatography-tandem mass spectrometry. Electrophoresis 2016; 37:913-23. [PMID: 26763089 DOI: 10.1002/elps.201500434] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/05/2015] [Accepted: 12/05/2015] [Indexed: 11/08/2022]
Abstract
Sugar-based ionic surfactants forming micelles are known to suppress ESI of various compounds due to decrease in surface tension upon micelle formation . For the first time, poly (sodium N-undecylenyl-α-d-glucopyranoside 4,6-hydrogen phosphate, (poly-α-d-SUGP) based surfactants with different chain lengths and head groups have been successfully synthesized, characterized, and applied as compatible chiral selector for MEKC-ESI-MS/MS. First, the effect of polymerization concentration of the monomer, α-d-SUGP, was evaluated by enantioseparation of one anionic compound (1,1'-binaphthyl-2,2'diyl-hydrogen phosphate) and one zwitterionic compound (dansylated phenylalanine) in MEKC-UV to find the optimum molar surfactant concentration for polymerization. Next, MEKC-UV and MEKC-MS were compared for the enantioseparation of 1,1'-binaphthyl-2,2'diyl-hydrogen phosphate. The influence of polymeric glucopyranoside based surfactant head groups and carbon chain lengths on chiral Rs was evaluated for two classes of cationic drugs (ephedrine alkaloids and β-blockers). Finally, enantioselective MEKC-MS of ephedrine alkaloids and β-blockers were profiled at their optimum pH 5.0 and 7.0, respectively, using 20 mM NH4 OAc, 25 mM poly-α-d-SUGP at 30 kV and 25°C under optimum spray chamber conditions. The LOD for most of the enantiomers ranges from 10 to 100 ng/mL with S/N of at least ≥3.0.
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Affiliation(s)
- Yijin Liu
- Department of Chemistry, Georgia State University, Atlanta, GA, US
| | - Baolin Wu
- Department of Chemistry, Georgia State University, Atlanta, GA, US
| | - Peng Wang
- Department of Chemistry, Georgia State University, Atlanta, GA, US
| | - Shahab A Shamsi
- Department of Chemistry, Georgia State University, Atlanta, GA, US
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7
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Liu Y, Jann M, Vandenberg C, Eap CB, Shamsi SA. Development of an enantioselective assay for simultaneous separation of venlafaxine and O-desmethylvenlafaxine by micellar electrokinetic chromatography-tandem mass spectrometry: Application to the analysis of drug-drug interaction. J Chromatogr A 2015; 1420:119-28. [PMID: 26460073 PMCID: PMC5025041 DOI: 10.1016/j.chroma.2015.09.088] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/27/2015] [Accepted: 09/29/2015] [Indexed: 11/30/2022]
Abstract
To-date, there has been no effective chiral capillary electrophoresis-mass spectrometry (CE-MS) method reported for the simultaneous enantioseparation of the antidepressant drug, venlafaxine (VX) and its structurally-similar major metabolite, O-desmethylvenlafaxine (O-DVX). This is mainly due to the difficulty of identifying MS compatible chiral selector, which could provide both high enantioselectivity and sensitive MS detection. In this work, poly-sodium N-undecenoyl-L,L-leucylalaninate (poly-L,L-SULA) was employed as a chiral selector after screening several dipeptide polymeric chiral surfactants. Baseline separation of both O-DVX and VX enantiomers was achieved in 15 min after optimizing the buffer pH, poly-L,L-SULA concentration, nebulizer pressure and separation voltage. Calibration curves in spiked plasma (recoveries higher than 80%) were linear over the concentration range 150-5000 ng/mL for both VX and O-DVX. The limit of detection (LOD) was found to be as low as 30 ng/mL and 21 ng/mL for O-DVX and VX, respectively. This method was successfully applied to measure the plasma concentrations of human volunteers receiving VX or O-DVX orally when co-administered without and with indinivar therapy. The results suggest that micellar electrokinetic chromatography electrospray ionization-tandem mass spectrometry (MEKC-ESI-MS/MS) is an effective low cost alternative technique for the pharmacokinetics and pharmacodynamics studies of both O-DVX and VX enantiomers. The technique has potential to identify drug-drug interaction involving VX and O-DVX enantiomers while administering indinivar therapy.
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Affiliation(s)
- Yijin Liu
- Center of Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, United States
| | - Michael Jann
- Health Science Center, University of North Texas, Fort Worth, TX 76107, United States
| | - Chad Vandenberg
- Midwestern University, Institute for Healthcare Innovation, Glendale, AZ 85308, United States
| | - Chin B Eap
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Department of Psychiatry, Lausanne University, Hospital of Cery, Prilly, Lausanne, Switzerland
| | - Shahab A Shamsi
- Center of Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, United States.
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8
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Kinde TF, Lopez TD, Dutta D. Electrophoretic extraction of low molecular weight cationic analytes from sodium dodecyl sulfate containing sample matrices for their direct electrospray ionization mass spectrometry. Anal Chem 2015; 87:2702-9. [PMID: 25664891 PMCID: PMC4455540 DOI: 10.1021/ac503903j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
While the use of sodium dodecyl sulfate (SDS) in separation buffers allows efficient analysis of complex mixtures, its presence in the sample matrix is known to severely interfere with the mass-spectrometric characterization of analyte molecules. In this article, we report a microfluidic device that addresses this analytical challenge by enabling inline electrospray ionization mass spectrometry (ESI-MS) of low molecular weight cationic samples prepared in SDS containing matrices. The functionality of this device relies on the continuous extraction of analyte molecules into an SDS-free solvent stream based on the free-flow zone electrophoresis (FFZE) technique prior to their ESI-MS analysis. The reported extraction was accomplished in our current work in a glass channel with microelectrodes fabricated along its sidewalls to realize the desired electric field. Our experiments show that a key challenge to successfully operating such a device is to suppress the electroosmotically driven fluid circulations generated in its extraction channel that otherwise tend to vigorously mix the liquid streams flowing through this duct. A new coating medium, N-(2-triethoxysilylpropyl) formamide, recently demonstrated by our laboratory to nearly eliminate electroosmotic flow in glass microchannels was employed to address this issue. Applying this surface modifier, we were able to efficiently extract two different peptides, human angiotensin I and MRFA, individually from an SDS containing matrix using the FFZE method and detect them at concentrations down to 3.7 and 6.3 μg/mL, respectively, in samples containing as much as 10 mM SDS. Notice that in addition to greatly reducing the amount of SDS entering the MS instrument, the reported approach allows rapid solvent exchange for facilitating efficient analyte ionization desired in ESI-MS analysis.
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Affiliation(s)
- Tristan F. Kinde
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Thomas D. Lopez
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Debashis Dutta
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
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9
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Tsioupi DA, Stefan-Vanstaden RI, Kapnissi-Christodoulou CP. Chiral selectors in CE: recent developments and applications. Electrophoresis 2013; 34:178-204. [PMID: 23161372 DOI: 10.1002/elps.201200239] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 08/14/2012] [Accepted: 08/14/2012] [Indexed: 01/01/2023]
Abstract
This review article provides an overview of the recent advances in enantioanalysis by use of electrophoretic techniques. Due to the big number of publications in the subject mentioned above, this article is focused on chiral method developments and applications published from 2008 until 2011, and it demonstrates chiral selectors used in CE. Numerous chiral selectors have been used over the years, and these include the cyclic and the linear oligo- and polysaccharides, the branched polysaccharides, the polymeric and monomeric surfactants, the macrocyclic and other antibiotics, and the crown ethers. Different dual-selector systems are also presented in this article, and the results are compared with those obtained by use of a single chiral selector. Finally, several pharmaceutical and biomedical applications based on chiral recognition are summarized.
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10
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Orlandini S, Gotti R, Furlanetto S. Multivariate optimization of capillary electrophoresis methods: a critical review. J Pharm Biomed Anal 2013; 87:290-307. [PMID: 23669025 DOI: 10.1016/j.jpba.2013.04.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 04/12/2013] [Indexed: 11/19/2022]
Abstract
In this article a review on the recent applications of multivariate techniques for optimization of electromigration methods, is presented. Papers published in the period from August 2007 to February 2013, have been taken into consideration. Upon a brief description of each of the involved CE operative modes, the characteristics of the chemometric strategies (type of design, factors and responses) applied to face a number of analytical challenges, are presented. Finally, a critical discussion, giving some practical advices and pointing out the most common issues involved in multivariate set-up of CE methods, is provided.
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Affiliation(s)
- Serena Orlandini
- Department of Chemistry "U. Schiff", University of Florence, Via U. Schiff 6, 50019 Sesto Fiorentino, Florence, Italy
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11
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He J, Shamsi SA. Application of polymeric surfactants in chiral micellar electrokinetic chromatography (CMEKC) and CMEKC coupled to mass spectrometry. Methods Mol Biol 2013; 970:319-348. [PMID: 23283788 DOI: 10.1007/978-1-62703-263-6_21] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The use of amino acid-based polymeric surfactants (a.k.a. molecular micelles) in chiral micellar electrokinetic chromatography (CMEKC) has been shown to be a successful separation mode for capillary electrophoresis (CE). In this mode, chiral compounds can be enantioseparated with high efficiency, high chiral selectivity, and versatility. This chapter describes the state-of-the art studies published in the past 5 years in CMEKC using polymeric surfactants. Recent trends in the compatibility of chiral polymeric surfactants with mass spectrometric (MS) detection suggest that this type of chiral selector may be the most promising ones for chiral CE-MS applications. The synthesis of new anionic and cationic MS-compatible polymeric surfactants and their utility in CMEKC and CMEKC-MS are demonstrated. Examples of how to run a typical CMEKC-MS experiment using univariate and multivariate optimization of CMEKC and MS parameters are discussed.
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Affiliation(s)
- Jun He
- Department of Chemistry, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA, USA
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12
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Tsioupi DA, Nicolaou IN, Moore L, Kapnissi-Christodoulou CP. Chiral separation of Huperzine A using CE - Method validation and application in pharmaceutical formulations. Electrophoresis 2012; 33:516-22. [DOI: 10.1002/elps.201100372] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 08/26/2011] [Accepted: 09/15/2011] [Indexed: 11/07/2022]
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He J, Shamsi SA. Chiral micellar electrokinetic chromatography-atmospheric pressure photoionization of benzoin derivatives using mixed molecular micelles. Electrophoresis 2011; 32:1164-75. [PMID: 21500208 DOI: 10.1002/elps.201000581] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Revised: 01/15/2011] [Accepted: 01/15/2011] [Indexed: 11/08/2022]
Abstract
In the present work we report, for the first time, the successful on-line coupling of chiral MEKC (CMEKC) to atmospheric pressure photoionization MS (APPI-MS). Four structurally similar neutral test solutes (e.g. benzoin (BNZ) derivatives) were successfully ionized by APPI-MS. The mass spectra in the positive ion mode showed that the protonated molecular ions of BNZs are not the most abundant fragment ions. Simultaneous enantioseparation by CMEKC and on-line APPI-MS detection of four photoinitiators, hydrobenzoin, BNZ, benzoin methyl ether, benzoin ethyl ether, were achieved using an optimized molar ratio of mixed molecular micelle of two polymeric chiral surfactants (polysodium N-undecenoxy carbonyl-L-leucinate and polysodium N-undecenoyl-L,L-leucylvalinate). The CMEKC conditions, such as voltage, chiral polymeric surfactant concentration, buffer pH, and BGE concentration, were optimized using a multivariate central composite design (CCD). The sheath liquid composition (involving %v/v methanol, dopant concentration, electrolyte additive concentration, and flow rate) and spray chamber parameters (drying gas flow rate, drying gas temperature, and vaporizer temperature) were also optimized with CCD. Models built based on the CCD results and response surface method were used to analyze the interactions between factors and their effects on the responses. The final overall optimum conditions for CMEKC-APPI-MS were also predicted and found in agreement with the experimentally optimized parameters.
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Affiliation(s)
- Jun He
- Department of Chemistry, Center of Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, USA
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Lu H, Chen G. Recent advances of enantioseparations in capillary electrophoresis and capillary electrochromatography. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2011; 3:488-508. [PMID: 32938063 DOI: 10.1039/c0ay00489h] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A comprehensive survey of recent developments and applications of capillary electromigration techniques for enantioseparations from January 2006 to June 2010 is presented. The techniques include capillary electrophoresis, chip capillary electrophoresis and capillary electrochromatography. The separation principles and the chiral recognition mechanisms are discussed. Additionally, on-line preconcentrations in chiral capillary electrophoresis are also reviewed.
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Affiliation(s)
- Huang Lu
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, China.
- Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou, Fujian 350108, China
| | - Guonan Chen
- Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, China.
- Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou, Fujian 350108, China
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15
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El Deeb S, Iriban MA, Gust R. MEKC as a powerful growing analytical technique. Electrophoresis 2010; 32:166-83. [PMID: 21171121 DOI: 10.1002/elps.201000398] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 09/30/2010] [Accepted: 09/30/2010] [Indexed: 11/11/2022]
Abstract
This review summarizes the principle and the developments in MEKC in terms of separation power, sensitivity, and detection approaches more than 25 years after its appearance. Newly used surfactants are mentioned. Classical and new sample concentration techniques in MEKC are described. The different detection approaches in MEKC with advantages, limitations, and future prospects are also discussed. This review highlights the wider application of MEKC in different analytical fields. Various recent selected applications of this technique in different analytical fields are reported.
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Affiliation(s)
- Sami El Deeb
- Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany
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16
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Pantůčková P, Gebauer P, Boček P, Křivánková L. Recent advances in CE-MS: Synergy of wet chemistry and instrumentation innovations. Electrophoresis 2010; 32:43-51. [PMID: 21171112 DOI: 10.1002/elps.201000382] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 08/17/2010] [Accepted: 08/17/2010] [Indexed: 01/29/2023]
Abstract
CE with MS detection is a hyphenated technique which greatly improves the ability of CE to deal with real samples, especially with those coming from biology and medicine, where the target analytes are present as trace amounts in very complex matrices. CE-MS is now almost a routine technique performed on commercially available instruments. It faces currently a tremendous development of the technique itself as well as of its wide application area. Great interest in CE-MS is reflected in the scientific literature by many original research articles and also by numerous reviews. The review presented here has a general scope and belongs to a series of regularly published reviews on the topic. It covers the literature from the last 2 years, since January 2008 till June 2010. It brings a critical selection of related literature sorted into groups reflecting the main topics of actual scientific interest: (i) innovations in CE-ESI-MS, (ii) use of alternative interfaces, and (iii) ways to enhance sensitivity. Special attention is paid to novel electrolyte systems amenable to CE-MS including nonvolatile BGEs, to advanced CE separation principles such as MEKC, MEEKC, chiral CE, and to the use of preconcentration techniques.
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Affiliation(s)
- Pavla Pantůčková
- Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic, Brno, Czech Republic
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17
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Gu C, Shamsi SA. CEC-atmospheric pressure ionization MS of pesticides using a surfactant-bound monolithic column. Electrophoresis 2010; 31:1162-1174. [PMID: 20349511 DOI: 10.1002/elps.200900739] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A surfactant bound poly (11-acrylaminoundecanoic acid-ethylene dimethacrylate) monolithic column was simply prepared by in situ co-polymerization of 11-acrylaminoundecanoic acid and ethylene dimethacrylate with 1-propanol, 1,4-butanediol and water as porogens in 100 microm id fused-silica capillary in one step. This column was used in CEC-atmospheric pressure photoionization (APPI)-MS system for separation and detection of N-methylcarbamates pesticides. Numerous parameters are optimized for CEC-APPI-MS. After evaluation of the mobile phase composition, sheath liquid composition and the monolithic capillary outlet position, a fractional factorial design was selected as a screening procedure to identify factors of ionization source parameters, such as sheath liquid flow rate, drying gas flow rate, drying gas temperature, nebulizing gas pressure, vaporizer temperature and capillary voltage, which significantly influence APPI-MS sensitivity. A face-centered central composite design was further utilized to optimize the most significant parameters and predict the best sensitivity. Under optimized conditions, S/Ns around 78 were achieved for an injection of 100 ng/mL of each pesticide. Finally, this CEC-APPI-MS method was successfully applied to the analysis of nine N-methylcarbamates in spiked apple juice sample after solid phase extraction with recoveries in the range of 65-109%.
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Affiliation(s)
- Congying Gu
- Department of Chemistry, Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, USA
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18
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Affiliation(s)
- Timothy J. Ward
- Millsaps College, 1701 N. State Street, Box 150306, Jackson, Mississippi 39210
| | - Karen D. Ward
- Millsaps College, 1701 N. State Street, Box 150306, Jackson, Mississippi 39210
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