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Liu H, Chen J, Chen M, Wang J, Qiu H. Recent development of chiral ionic liquids for enantioseparation in liquid chromatography and capillary electrophoresis: A review. Anal Chim Acta 2023; 1274:341496. [PMID: 37455089 DOI: 10.1016/j.aca.2023.341496] [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: 11/22/2022] [Revised: 06/04/2023] [Accepted: 06/05/2023] [Indexed: 07/18/2023]
Abstract
Ionic liquids (ILs), which are salts in a molten state below 100 °C, have become a hot topic of research in various fields because of their negligible vapour pressure, high thermal stability, and tunable viscosity. Chiral ionic liquids (CILs) can be applied in chromatography and capillary electrophoresis fields to improve the performance of enantiomeric separation, such as chiral stationary phases (CSPs) and mobile phase additives in high-performance liquid chromatography (HPLC); CSPs in gas chromatography (GC); and background electrolyte additives (BGE), chiral ligands and chiral selectors (CSs) in capillary electrophoresis (CE). This review focuses on the applications of CILs in HPLC and CE for the separation of enantiomers in the past five years. The mechanism for separating enantiomers was explained, and the prospect of the application of CILs in chiral liquid chromatography (LC) and CE analysis was also discussed.
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Affiliation(s)
- Huifeng Liu
- Department of Chemistry, College of Sciences, Northeastern University, Shenyang, 110819, China; CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Jia Chen
- CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.
| | - Mingli Chen
- Department of Chemistry, College of Sciences, Northeastern University, Shenyang, 110819, China
| | - Jianhua Wang
- Department of Chemistry, College of Sciences, Northeastern University, Shenyang, 110819, China.
| | - Hongdeng Qiu
- CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China; College of Chemistry and Chemical Engineering, Gannan Normal University, Ganzhou, 341000, China.
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2
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Patel VD, Shamsi SA, Sutherland K. Capillary electromigration techniques coupled to mass spectrometry: Applications to food analysis. Trends Analyt Chem 2021; 139. [DOI: 10.1016/j.trac.2021.116240] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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3
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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: 27] [Impact Index Per Article: 9.0] [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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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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Establishing repeatability and ruggedness of chiral separations in micellar electrokinetic chromatography mass spectrometry: Combined use of covalently bonded capillary column and molecular micelles. J Chromatogr A 2019; 1617:460835. [PMID: 31928773 DOI: 10.1016/j.chroma.2019.460835] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 12/24/2019] [Accepted: 12/29/2019] [Indexed: 10/25/2022]
Abstract
Although micellar electrokinetic chromatography-mass spectrometry (MEKC-MS) using bare silica capillary filled with molecular micelles is an advantageous hyphenated technique for chiral analysis, it is still in the developmental stage. This is mainly because of the lower repeatability of retention time and peak area associated with the difficulty in controlling electroosmotic flow on bare silica capillaries. Besides the lower robustness and electrospray erosion of the fused-silica capillary tip, the lifetime is limited for 10-15 runs per capillary column. We have tested a new MEKC-MS method to eradicate this problem using a covalently bonded 2-acrylamido-2-methyl-1-propane-sulfonic acid (AMPS) column filled with free floating molecular micelles, polysodium N-undecenoxy carbonyl-L-leucinate (poly-L-SUCL). Simultaneous enantiomeric separations and MS/MS detection of three β-blockers [atenolol (ATEN), metoprolol (METO) and, pindolol (PINDO)] was achieved within 25 min with improved column lifetime of at least 45-50 runs. Excellent repeatability of retention time was observed for β-blockers, as evidenced by the relative standard deviation of less than 2% and 3% for intra-capillary and inter-capillary column, respectively. The linear calibration range of both β-blockers was simultaneously established using enantiomers of PINDO as an internal standard. The limit of detection and the lower limit of quantitation were 0.2 μg/mL and 0.5 μg/mL, respectively, for both ATEN and METO. Acceptable recovery of the enantiomeric content of the commercial METO tablet (98-99.5%) and ATEN tablet (89-92.5%) were obtained with adequate system suitability for the precision of peak area (≤10% RSD) under optimum conditions. The developed MEKC-MS approach was extended, which provided broader repeatibility of chiral separation to a panel of primary, secondary and tertiary amines as well as one anionic chiral compound.
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Abstract
Capillary electrophoresis (CE) is a well-established and one of the most powerful separation techniques in the field of chiral separations. Its hyphenation with mass spectrometry (MS) combines both the high separation efficiency and low sample consumption of CE and the high sensitivity and structural information of MS. Thus, the outstanding chiral resolution power of CE along with the MS advantages makes CE-MS a perfect combination to achieve sensitive enantioseparations. This chapter describes three representative examples of different approaches used in the chiral analysis of amino acids in biological fluids by CE-MS. The first methodology uses the partial filling technique to avoid the entry of cyclodextrins in the MS source. The second method shows the possibility to carry out the direct coupling EKC-MS even when a relative high concentration of a native cyclodextrin is used as chiral selector. The last example illustrates an alternative strategy based on the formation of stable diastereomers between an enantiomerically pure chiral reagent and the amino acids enantiomers which can be separated in an achiral environment.
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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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Cheng J, Chen DDY. Nonaqueous capillary electrophoresis mass spectrometry method for determining highly hydrophobic peptides. Electrophoresis 2017; 39:1216-1221. [PMID: 28990192 DOI: 10.1002/elps.201700364] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/03/2017] [Accepted: 10/04/2017] [Indexed: 01/07/2023]
Abstract
A nonaqueous capillary electrophoresis mass spectrometry (NACE-MS) method was developed to separate and determine highly hydrophobic temporin peptides. The nonaqueous background electrolyte solution was a mixture of 20% acetonitrile, 78% methanol and 2% formic acid, with 20 mM ammonium formate. The separation of six peptides was completed within 12 min. The CE system was connected to a triple quadrupole mass spectrometer operating in MRM mode using a chemical modifier solution of 2 mM ammonium formate in ethanol with the flow through microvial interface. The mass spectrometer offered a second dimension of separation for peptides having identical migration times but different structures. The new method represents the first system capable of reliably determining hydrophobic peptides without using reversed phase liquid chromatography mass spectrometry.
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Affiliation(s)
- Jianhui Cheng
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - David D Y Chen
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
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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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10
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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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11
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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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Zhang J, Du Y, Zhang Q, Lei Y. Evaluation of vancomycin-based synergistic system with amino acid ester chiral ionic liquids as additives for enantioseparation of non-steroidal anti-inflamatory drugs by capillary electrophoresis. Talanta 2014; 119:193-201. [DOI: 10.1016/j.talanta.2013.10.042] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 10/16/2013] [Accepted: 10/20/2013] [Indexed: 10/26/2022]
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Liu D, Li Y, Deng J, Yang W. Helix-sense-selective polymerization of achiral substituted acetylene in chiral micelles for preparing optically active polymer nanoparticles: Effects of chiral emulsifiers. POLYMER 2014. [DOI: 10.1016/j.polymer.2013.12.050] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Zhang J, Du Y, Zhang Q, Chen J, Xu G, Yu T, Hua X. Investigation of the synergistic effect with amino acid-derived chiral ionic liquids as additives for enantiomeric separation in capillary electrophoresis. J Chromatogr A 2013; 1316:119-26. [DOI: 10.1016/j.chroma.2013.09.064] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Revised: 09/14/2013] [Accepted: 09/17/2013] [Indexed: 11/25/2022]
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Abstract
Capillary electrophoresis (CE) has matured to one of the major liquid phase enantiodifferentiation techniques since the first report in 1985. This can be primarily attributed to the flexibility as well as the various modes available including electrokinetic chromatography (EKC), micellar electrokinetic chromatography (MEKC), and microemulsion electrokinetic chromatography (MEEKC). In contrast to chromatographic techniques, the chiral selector is mobile in the background electrolyte. Furthermore, a large variety of chiral selectors are available that can be easily combined in the same separation system. In addition, the migration order of the enantiomers can be adjusted by a number of approaches. In CE enantiodifferentiations the separation principle is comparable to chromatography while the principle of the movement of the analytes in the capillary is based on electrophoretic phenomena. The present chapter will focus on mechanistic aspects of CE enantioseparations including enantiomer migration order and the current understanding of selector-selectand structures. Selected examples of the basic enantioseparation modes EKC, MEKC, and MEEKC will be discussed.
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Affiliation(s)
- Gerhard K E Scriba
- Department of Pharmaceutical/Medicinal Chemistry, Friedrich Schiller University Jena, Philosophenweg 14, 07743, Jena, Germany,
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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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Development of a chiral micellar electrokinetic chromatography-tandem mass spectrometry assay for simultaneous analysis of warfarin and hydroxywarfarin metabolites: application to the analysis of patients serum samples. J Chromatogr A 2012; 1271:207-16. [PMID: 23246089 DOI: 10.1016/j.chroma.2012.11.046] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 11/14/2012] [Accepted: 11/19/2012] [Indexed: 11/22/2022]
Abstract
The enantioseparation of warfarin (WAR) along with the five positional and optical isomers is challenging because of the difficulty to simultaneously separate and quantitate these chiral compounds. Currently, no effective chiral CE-MS methods exist for the simultaneous enantioseparation of WAR and all its hydroxylated metabolites in a single run. Polymeric surfactants (aka. molecular micelles) are particularly compatible with micellar electrokinetic chromatography-mass spectrometry (MEKC-MS) because they have a wider elution window for enantioseparation and do not interfere with the MS detection of chiral drugs. Using polysodium N-undecenoyl-L,L-leucylvalinate (poly-L,L-SULV) as a chiral pseudophase in MEKC-MS baseline separation of WAR, its five metabolites along with the internal standard was obtained in 45 min. This is in comparison to 100 min required for separation of the same mixture with packed column CEC-MS using a vancomycin chiral stationary phase. Serum samples were extracted with mixed-mode anion-exchange (MAX) cartridge with recoveries of greater than 85.2% for all WAR and hydroxywarfarin (OH-WAR) metabolites. Utilizing the tandem MS and multiple reaction monitoring mode, the MEKC-MS/MS method was used to simultaneously generate calibration curves over a concentration range from 2 to 5000 ng/mL for R- and S-warfarin, 5 to 1000 ng/mL for R- and S-6-, 7-, 8- and 10-OH-WAR and 10 to 1000 ng/mL for R and S-4'-OH-WAR. For the first time, the limits of detection and quantitation for most WAR metabolites by MEKC-MS/MS were found to be at levels of 2 and 5 ng/mL, respectively. The method was successfully applied for the first time to analyze WAR and its metabolites in plasma samples of 55 patients undergoing WAR therapy, demonstrating the potential of chiral MEKC-MS/MS method to accurately quantitate with high sensitivity.
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Espada A, Molina-Martin M. Capillary electrophoresis and small molecule drug discovery: a perfect match? Drug Discov Today 2012; 17:396-404. [PMID: 22387356 DOI: 10.1016/j.drudis.2012.02.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 12/19/2011] [Accepted: 02/10/2012] [Indexed: 01/27/2023]
Abstract
Capillary electrophoresis (CE) is an analytical technique based on the separation of the analytes within a capillary owing to their different electrophoretic mobilities. It is widely used in pharmaceutical analyses owing to its versatility and high separation power. However, its penetration into the drug discovery scene has been relatively limited until recent years. Several factors have contributed to this low implementation, including the maturity of liquid chromatography, the scarcity of experienced CE practitioners, and certain limitations intrinsic to the technique. Recently, instrumental improvements and the growing demand for analytical information have lead to a continuously expanding range of routine electrophoretic applications throughout pharmaceutical discovery and development. In this article we review CE fundamentals, review well-established CE methodologies in drug discovery of small molecules and discuss trends that, in our opinion, might emerge in the coming years.
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Affiliation(s)
- Alfonso Espada
- Analytical Technologies Department, Centro de Investigación Lilly SA, Avda de la Industria 30, 28108-Alcobendas, Madrid, Spain
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19
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Stanley B, Lucy CA. Micellar electrokinetic chromatography with acid labile surfactant. J Chromatogr A 2012; 1226:55-60. [DOI: 10.1016/j.chroma.2011.09.065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 09/23/2011] [Accepted: 09/23/2011] [Indexed: 01/12/2023]
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20
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Płotka JM, Biziuk M, Morrison C. Common methods for the chiral determination of amphetamine and related compounds II. Capillary electrophoresis and nuclear magnetic resonance. Trends Analyt Chem 2012. [DOI: 10.1016/j.trac.2011.06.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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21
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Recent progress in capillary electrophoretic analysis of amino acid enantiomers. J Chromatogr B Analyt Technol Biomed Life Sci 2011; 879:3078-95. [DOI: 10.1016/j.jchromb.2011.03.016] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 03/02/2011] [Accepted: 03/06/2011] [Indexed: 11/20/2022]
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22
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Aturki Z, D'Orazio G, Rocco A, Fanali S. Advances in the enantioseparation of β-blocker drugs by capillary electromigration techniques. Electrophoresis 2011; 32:2602-28. [PMID: 21905049 DOI: 10.1002/elps.201100153] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 04/08/2011] [Accepted: 04/09/2011] [Indexed: 11/07/2022]
Abstract
β-Blocker drugs or β-adrenergic blocking agents are an important class of drugs, prescribed with great frequency. They are used for various diseases, particularly for the treatment of cardiac arrhythmias, cardioprotection after myocardial infarction (heart attack), and hypertension. Almost all β-blocker drugs possess one or more stereogenic centers; however; only some of them are administered as single enantiomers. Since both enantiomers can differ in their pharmacological and toxicological properties, enantioselective analytical methods are required not only for pharmacodynamic and pharmacokinetic studies but also for quality control of pharmaceutical preparations with the determination of enantiomeric purity. In addition to the chromatographic tools, in recent years, capillary electromigration techniques (CE, CEC, and MEKC) have been widely used for enantioselective purposes employing a variety of chiral selectors, e.g. CDs, polysaccharides, macrocyclic antibiotics, proteins, chiral ion-paring agents, etc. The high separation efficiency, rapid analysi,s and low consumption of reagents of electromigration methods make them a very attractive alternative to the conventional chromatographic methods. In this review, the development and applications of electrodriven methods for the enantioseparation of β-blocker drugs are reported. The papers concerning this topic, published from January 2000 until December 2010, are summarised here. Particular attention is given to the coupling of chiral CE and CEC methods to MS, as this detector provides high sensitivity and selectivity.
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Affiliation(s)
- Zeineb Aturki
- Istituto di Metodologie Chimiche, Consiglio Nazionale delle Ricerche, Area della Ricerca di Roma, Monterotondo Scalo, Rome, Italy
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Helix-Sense-Selective Polymerization of Achiral Substituted Acetylenes in Chiral Micelles. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201006658] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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24
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Luo X, Deng J, Yang W. Helix-Sense-Selective Polymerization of Achiral Substituted Acetylenes in Chiral Micelles. Angew Chem Int Ed Engl 2011; 50:4909-12. [DOI: 10.1002/anie.201006658] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Indexed: 11/07/2022]
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25
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Palmer CP, Keeffer A, Hilder EF, Haddad PR. Retention behavior and selectivity of a latex nanoparticle pseudostationary phase for electrokinetic chromatography. Electrophoresis 2011; 32:588-94. [DOI: 10.1002/elps.201000470] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 11/01/2010] [Accepted: 11/07/2010] [Indexed: 11/11/2022]
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26
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Huang L, Lin Q, Chen Y, Chen G. Transient isotachophoresis with field-amplified sample injection for on-line preconcentration and enantioseparation of some β-agonists. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2011; 3:294-298. [PMID: 32938027 DOI: 10.1039/c0ay00556h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transient isotachophoresis with field-amplified sample injection (FASI), using β-CD as the chiral selector and tetrabutylammonium hydroxide (TBAOH) as the additive, was applied for on-line preconcentration and enantioseparation of three β-agonists, namely, cimaterol, clenbuterol and terbutaline. The experimental conditions for both simultaneous enantioseparation and on-line preconcentration methods have been investigated in detail. Under the optimum conditions, the detection limits (defined as S/N = 3) of this method were found to be 1 ng mL-1 for all three pairs of β-agonists enantiomers. Compared with conventional electrokinetic injection, the enhancement factors were greatly improved to be 250-fold. Finally, the proposed method has been applied for the analysis of human urine samples.
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Affiliation(s)
- Lu Huang
- Ministry of Education Key Laboratory of Analysis and Detection Technology for Food Safety (Fuzhou University), Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, China.
- Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou, Fujian 350108, China
| | - Qi Lin
- Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou, Fujian 350108, China
| | - Yiting Chen
- Ministry of Education Key Laboratory of Analysis and Detection Technology for Food Safety (Fuzhou University), 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 Technology for Food Safety (Fuzhou University), Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, China.
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Caslavska J, Thormann W. Stereoselective determination of drugs and metabolites in body fluids, tissues and microsomal preparations by capillary electrophoresis (2000–2010). J Chromatogr A 2011; 1218:588-601. [DOI: 10.1016/j.chroma.2010.08.072] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 08/20/2010] [Accepted: 08/25/2010] [Indexed: 10/19/2022]
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28
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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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Palmer CP, Hilder EF, Quirino JP, Haddad PR. Electrokinetic chromatography and mass spectrometric detection using latex nanoparticles as a pseudostationary phase. Anal Chem 2010; 82:4046-54. [PMID: 20402470 DOI: 10.1021/ac902922u] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The utility of novel latex nanoparticles as pseudostationary phases for electrokinetic chromatography with UV and mass spectrometric detection is demonstrated. The nanoparticles are synthesized using ab initio RAFT (reversible addition-fragmentation chain transfer) in emulsion polymerization, which yields small (63 nm) particles with a narrow size distribution, a hydrophobic core, and an ionic shell. The nanoparticles are shown to provide efficient and selective separations, with retention and separation selectivity dominated by hydrophobic interactions. The nanoparticles are highly retentive, such that they are effective at relatively low concentrations. Addition of the nanoparticles to the background electrolyte at these concentrations has a minor effect on the noise with UV detection, no measurable effect on the separation current, and minor effects on analyte ionization efficiency during electrospray ionization. The nanoparticles do not cause fouling or degradation of the electrospray-mass spectrometer interface even after several weeks of use. The combination of online sample preconcentration via sweeping and selective mass spectrometric detection yields low detection limits (10-16 ppb), particularly for more hydrophobic compounds.
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Affiliation(s)
- Christopher P Palmer
- Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59803, USA.
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30
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Abstract
This review article addresses the developments and applications of capillary electromigration methods coupled on-line with MS for chiral analysis. The multiple enantiomeric applications of this hyphenated technology are covered including chiral analysis of drugs, food compounds, pesticides, natural metabolites, etc. in different matrices such as plasma, urine, medicines, foods, etc. This work intends to provide an updated overview (including works published till September 2009) on the principal chiral applications carried out by CZE-MS, CEC-MS and MEKC-MS, discussing their main advantages and drawbacks in all their different areas of application as well as their foreseeable development in the not too distant future.
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Affiliation(s)
- Carolina Simó
- Department of Food Analysis, Institute of Industrial Fermentations (CSIC), Madrid, Spain
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31
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Hu SQ, Chen YL, Zhu HD, Shi HJ, Yan N, Chen XG. Effect of molecular structure of tartrates on chiral recognition of tartrate–boric acid complex chiral selectors in chiral microemulsion electrokinetic chromatography. J Chromatogr A 2010; 1217:5529-35. [DOI: 10.1016/j.chroma.2010.06.063] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 06/18/2010] [Accepted: 06/24/2010] [Indexed: 11/26/2022]
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32
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Somsen GW, Mol R, de Jong GJ. On-line coupling of electrokinetic chromatography and mass spectrometry. J Chromatogr A 2010; 1217:3978-91. [DOI: 10.1016/j.chroma.2010.01.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 12/23/2009] [Accepted: 01/08/2010] [Indexed: 11/27/2022]
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Mikus P, Maráková K. Advanced CE for chiral analysis of drugs, metabolites, and biomarkers in biological samples. Electrophoresis 2010; 30:2773-802. [PMID: 19653234 DOI: 10.1002/elps.200900173] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An analysis of recent trends indicates that CE can show real advantages over chromatographic methods in ultratrace enantioselective determination of biologically active compounds in complex biological matrices. It is due to high separation efficiency and many applicable in-capillary electromigration effects in CE (countercurrent migration, stacking effects) enhancing significantly (enantio)separability and enabling effective sample preparation (preconcentration, purification, analyte derivatization). Other possible on-line combinations of CE, such as column coupled CE-CE techniques and implementation of nonelectrophoretic techniques (extraction, membrane filtration, flow injection) into CE, offer additional approaches for highly effective sample preparation and separation. CE matured to a highly flexible and compatible technique enabling its hyphenation with powerful detection systems allowing extremely sensitive detection (e.g. LIF) and/or structural characterization of analytes (e.g. MS). Within the last decade, more as well as less conventional analytical on-line approaches have been effectively utilized in this field and their practical potentialities are demonstrated on many new application examples in this article. Here, three basic areas of (enantioselective) drug bioanalysis are highlighted and supported by a brief theoretical description of each individual approach in a compact review structure (to create integrated view on the topic), including (i) progressive enantioseparation approaches and new enantioselective agents, (ii) in-capillary sample preparation (preconcentration, purification, derivatization), and (iii) detection possibilities related to enhanced sensitivity and structural characterization.
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Affiliation(s)
- Peter Mikus
- Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic.
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34
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Viglio S, Fumagalli M, Ferrari F, Iadarola P. MEKC: A powerful tool for the determination of amino acids in a variety of biomatrices. Electrophoresis 2010; 31:93-104. [DOI: 10.1002/elps.200900366] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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35
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Luo X, Li L, Deng J, Guo T, Yang W. Asymmetric catalytic emulsion polymerization in chiral micelles. Chem Commun (Camb) 2010; 46:2745-7. [DOI: 10.1039/b926134f] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cao J, Li B, Chang YX, Li P. Direct on-line analysis of neutral analytes by dual sweeping via complexation and organic solvent field enhancement in nonionic MEKC. Electrophoresis 2009; 30:1372-9. [PMID: 19382135 DOI: 10.1002/elps.200800523] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Conventionally, neutral compounds cannot be separated by nonionic micelle capillary electrophoresis. In this report, the development of a novel on-line preconcentration technique combining dual sweeping based on complexation and organic solvent field enhancement is applied to the sensitive and selective analysis of three neutral glucosides: ginsenoside Rf, ginsenoside Rg1, and ginsenoside Re. Nonionic micelle detectability by CE is demonstrated through effective focusing of large sample volumes (up to 38% capillary length) using a dual sweeping mode. This results in a 50- to 130-fold improvement in the LODs relative to conventional injection method. Neutral compounds sweeping is examined in terms of analyte mobility dependence on borate complexation, solvent viscosity difference, and Brij-35 interaction. Enhanced focusing performance by this hyphenated method was demonstrated by a greater than fourfold reduction in glucoside bandwidth, as compared with common sweeping (devoid of organic solvent-mediated sweeping method in the sample matrices). Moreover, separation efficiencies greater than a million theoretical plates can be achieved by sweeping large sample volumes into narrow zones. The designated method was also tested for its ability to determine the presence of glucosides in the crude extracts obtained from plant sample.
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Affiliation(s)
- Jun Cao
- Key Laboratory of Modern Chinese Medicines (China Pharmaceutical University), Ministry of Education and Department of Pharmacognosy, China Pharmaceutical University, Nanjing, PR China
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37
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Castro-Puyana M, Drewnowska R, Pérez-Fernández V, Ángeles García M, Crego AL, Marina ML. Simultaneous separation of epinephrine and norepinephrine enantiomers by EKC: Application to the analysis of pharmaceutical formulations. Electrophoresis 2009; 30:2947-54. [DOI: 10.1002/elps.200900250] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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38
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Huang L, Lin JM, Yu L, Xu L, Chen G. Improved simultaneous enantioseparation of β-agonists in CE using β-CD and ionic liquids. Electrophoresis 2009; 30:1030-6. [DOI: 10.1002/elps.200800483] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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39
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He J, Shamsi SA. Multivariate approach for the enantioselective analysis in micellar electrokinetic chromatography-mass spectrometry. I. Simultaneous optimization of binaphthyl derivatives in negative ion mode. J Chromatogr A 2009; 1216:845-56. [PMID: 19110258 PMCID: PMC2861921 DOI: 10.1016/j.chroma.2008.11.093] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2008] [Revised: 11/10/2008] [Accepted: 11/13/2008] [Indexed: 11/30/2022]
Abstract
A mixture of two molecular micelles polysodium N-undecenoxy carbonyl-L-leucinate, (poly-L-SUCL) and polysodium N-undecanoyl leucylvalinate, (poly-L-SULV) was utilized in micellar electrokinetic chromatography-electrospray ionization-mass spectrometry (MEKC-ESI-MS) to simultaneously separate and detect enantiomers of binaphthyl derivatives. Separation parameters such as background buffer composition, voltage, temperature, and nebulizer pressure were optimized using a multivariate central composite design (CCD). Baseline enantioseparation for both analytes was achieved. The CCD was also used in the optimization of sheath liquid and spray chamber parameters to achieve optimum ESI-MS response. The results demonstrate that CCD is a powerful tool for the optimization of MEKC-MS parameters and the response surface model analysis can provide in-depth statistical understandings of the significant factors required to achieve maximum enantioresolution and ESI-MS sensitivity.
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Affiliation(s)
- Jun He
- Department of Chemistry, Center of Biotechnology and Drug Design, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
| | - Shahab A. Shamsi
- Department of Chemistry, Center of Biotechnology and Drug Design, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
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40
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Silva M. Micellar electrokinetic chromatography: Methodological and instrumental advances focused on practical aspects. Electrophoresis 2009; 30:50-64. [DOI: 10.1002/elps.200800414] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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41
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Palmer CP. Recent progress in the use of ionic polymers as pseudostationary phases for electrokinetic chromatography. Electrophoresis 2009; 30:163-8. [DOI: 10.1002/elps.200800420] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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42
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Castro-Puyana M, García-Ruiz C, Crego AL, Marina ML. Development of a CE-MS2method for the enantiomeric separation of L/D-carnitine: Application to the analysis of infant formulas. Electrophoresis 2009; 30:337-48. [DOI: 10.1002/elps.200800163] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Preinerstorfer B, Lämmerhofer M, Lindner W. Advances in enantioselective separations using electromigration capillary techniques. Electrophoresis 2009; 30:100-32. [DOI: 10.1002/elps.200800607] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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44
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Chiral separation by capillary electromigration techniques. J Chromatogr A 2008; 1204:140-56. [DOI: 10.1016/j.chroma.2008.07.071] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 06/27/2008] [Accepted: 07/08/2008] [Indexed: 11/19/2022]
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45
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Hommerson P, Khan AM, de Jong GJ, Somsen GW. Comparison of electrospray ionization and atmospheric pressure photoionization for coupling of micellar electrokinetic chromatography with ion trap mass spectrometry. J Chromatogr A 2008; 1204:197-203. [DOI: 10.1016/j.chroma.2008.04.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 03/29/2008] [Accepted: 04/09/2008] [Indexed: 11/27/2022]
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46
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Huang L, Lin JM, Yu L, Xu L, Chen G. Field-amplified on-line sample stacking for simultaneous enantioseparation and determination of some β-blockers using capillary electrophoresis. Electrophoresis 2008; 29:3588-94. [DOI: 10.1002/elps.200700811] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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47
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Abstract
Recent research and development efforts concerning polymeric pseudostationary phases (PSPs) for electrokinetic chromatography are reviewed. The introduction of new materials, characterization of structural effects on performance and selectivity, applications, and the use of polymeric PSPs with mass spectrometric detection are considered. Very interesting results concerning the effects of polymer structure have been reported. Significant developments have also been reported in the development of novel applications of polymeric PSPs, particularly for sample preconcentration using micellar affinity gradient focusing. The use of mass spectrometric detection with electrokinetic chromatography has seen significant development, and recent reports indicate that this is a robust and sensitive approach.
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Affiliation(s)
- Christopher P Palmer
- Australian Centre for Research, on Separation Science (ACROSS), School of Chemistry, University of Tasmania, Hobart, Tasmania, Australia.
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48
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Kostal V, Katzenmeyer J, Arriaga EA. Capillary electrophoresis in bioanalysis. Anal Chem 2008; 80:4533-50. [PMID: 18484738 DOI: 10.1021/ac8007384] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Vratislav Kostal
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Williams AA, Fakayode SO, Alptürk O, Jones CM, Lowry M, Strongin RM, Warner IM. Determination of enantiomeric compositions of analytes using novel fluorescent chiral molecular micelles and steady state fluorescence measurements. J Fluoresc 2008; 18:285-96. [PMID: 17985217 PMCID: PMC2662355 DOI: 10.1007/s10895-007-0268-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Accepted: 10/08/2007] [Indexed: 11/30/2022]
Abstract
Novel fluorescent chiral molecular micelles (FCMMs) were synthesized, characterized, and employed as chiral selectors for enantiomeric recognition of non-fluorescent chiral molecules using steady state fluorescence spectroscopy. The sensitivity of the fluorescence technique allowed for investigation of low concentrations of chiral selector (3.0 x 10(-5) M) and analyte (5.0 x 10(-6) M) to be used in these studies. The chiral interactions of glucose, tartaric acid, and serine in the presence of FCMMs poly(sodium N-undecanoyl-L-tryptophanate) [poly-L-SUW], poly(sodium N-undecanoyl-L-tyrosinate) [poly-L-SUY], and poly(sodium N-undecanoyl-L-phenylalininate) [poly-SUF] were based on diastereomeric complex formation. Poly-L-SUW had a significant fluorescence emission spectral difference as compared to poly-L-SUY and poly-L-SUF for the enantiomeric recognition of glucose, tartaric acid, and serine. Studies with the hydrophobic molecule alpha-pinene suggested that poly-L-SUY and poly-L-SUF had better chiral discrimination ability for hydrophobic analytes as compared to hydrophilic analytes. Partial-least-squares regression modeling (PLS-1) was used to correlate changes in the fluorescence emission spectra of poly-L-SUW due to varying enantiomeric compositions of glucose, tartaric acid, and serine for a set of calibration samples. Validation of the calibration regression models was determined by use of a set of independently prepared samples of the same concentration of chiral selector and analyte with varying enantiomeric composition. Prediction ability was evaluated by use of the root-mean-square percent relative error (RMS%RE) and was found to range from 2.04 to 4.06%.
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Affiliation(s)
- Alicia A. Williams
- Department of Chemistry, Louisiana State University, 434 Choppin Hall, Baton Rouge, LA 70803, USA, e-mail:
| | - Sayo O. Fakayode
- Department of Chemistry, Winston-Salem State University, Winston-Salem, NC 27110, USA
| | - Onur Alptürk
- Department of Chemistry, Louisiana State University, 434 Choppin Hall, Baton Rouge, LA 70803, USA, e-mail:
| | - Christina M. Jones
- Department of Chemistry, Louisiana State University, 434 Choppin Hall, Baton Rouge, LA 70803, USA, e-mail:
| | - Mark Lowry
- Department of Chemistry, Louisiana State University, 434 Choppin Hall, Baton Rouge, LA 70803, USA, e-mail:
| | - Robert M. Strongin
- Department of Chemistry, Portland State University, Portland, OR 97207, USA
| | - Isiah M. Warner
- Department of Chemistry, Louisiana State University, 434 Choppin Hall, Baton Rouge, LA 70803, USA, e-mail:
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50
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Amundsen LK, Kokkonen JT, Sirén H. Comparison of partial filling MEKC analyses of steroids with use of ESI-MS and UV spectrophotometry. J Sep Sci 2008; 31:803-13. [DOI: 10.1002/jssc.200700657] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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