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Readel ER, Dhaubhadel U, Patel A, Armstrong DW. Variable fragmentation and ionization of amyloid-beta epimers and isomers. Anal Bioanal Chem 2023; 415:6799-6807. [PMID: 37787853 DOI: 10.1007/s00216-023-04958-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/25/2023] [Accepted: 09/12/2023] [Indexed: 10/04/2023]
Abstract
While the existence of D-amino acids in peptides and proteins has recently been accepted in higher forms of life, their roles and importance are yet to be understood. The lack of analytical methods present for such epimeric and/or isomeric analyses often limits developments in the field. Studies have shown the elevated presence of epimeric and isomeric modifications to amyloid-beta (Aβ) peptides extracted from Alzheimer's disease patients. These modifications most frequently occur through aspartic acid and serine residues. Because such peptides are indistinguishable by mass alone, selective liquid chromatography tandem mass spectrometry analysis is required to differentiate such peptides. Herein, we examine MS/MS of tryptic fragments of Aβ peptides containing D-Asp, L-iso-Asp, D-iso-Asp, and/or D-Ser modifications. Peptide ionizability and fragmentation are explored through selected reaction monitoring, selected ion monitoring, and product ion scan. The results show the variability of ionization and fragmentation for many "identical mass peptides" and how these differences can affect the analysis of isomeric and epimeric peptides.
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Affiliation(s)
- Elizabeth R Readel
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Umang Dhaubhadel
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Arzoo Patel
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Daniel W Armstrong
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA.
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2
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Vargas-Caporali J, Juaristi E. Fundamental Developments of Chiral Phase Chromatography in Connection with Enantioselective Synthesis of β-Amino Acids. Isr J Chem 2017. [DOI: 10.1002/ijch.201700011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Jorge Vargas-Caporali
- Departamento de Química; Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional Avenida IPN No. 2508; 07360 Ciudad de México México
| | - Eusebio Juaristi
- Departamento de Química; Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional Avenida IPN No. 2508; 07360 Ciudad de México México
- El Colegio Nacional; Luis González Obregón No. 23, Centro Histórico 06020 Ciudad de México México
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3
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Separation of peptides on superficially porous particle based macrocyclic glycopeptide liquid chromatography stationary phases: consideration of fast separations. Anal Bioanal Chem 2017; 409:2437-2447. [PMID: 28215026 DOI: 10.1007/s00216-017-0190-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/20/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
Abstract
Macrocyclic glycopeptide based liquid chromatography stationary phases are known for their highly selective peptide separations. Fast and ultrafast (t R < 1 min) high-efficiency separations were achieved with superficially porous particle (SPP)-based stationary phases. Separations of pharmaceutically important classes of peptides such as enkephalins and bradykinins have been achieved in less than 5 min in isocratic elution modes. Selectivity for peptides structurally similar to one another was increased with use of teicoplanin-based stationary phases compared with commercial C18 stationary phases. Ultrafast isocratic separations of structurally related peptides were achieved with teicoplanin- and vancomycin-based short SPP columns. Acidic mobile phases produced better separations. Ammonium formate was the optimal mobile phase buffer additive. Use of an appropriate combination of a macrocyclic glycopeptide stationary phase and a mobile phase permits faster and more electrospray ionization mass spectrometry compatible isocratic separations than previous gradient approaches. The tryptic peptide separation characteristics of the teicoplanin stationary phase are demonstrated. Additionally, compared with commercial C18 stationary phases, teicoplanin showed tryptic peptide separations with different selectivities. Graphical Abstract Ultrafast separation of enkephalin peptide epimers.
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4
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Watarai H, Kurahashi Y. Chiral Recognition of 2-Alkylalcohols with Magnetic Circular Dichroism Measurement of Porphyrin J-Aggregate on Silica Gel Plate. Anal Chem 2016; 88:4619-23. [DOI: 10.1021/acs.analchem.6b00515] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hitoshi Watarai
- Institute for NanoScience
Design, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Yuriko Kurahashi
- Institute for NanoScience
Design, Osaka University, Toyonaka, Osaka 560-8531, Japan
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Polak B, Balasa K, Dzido T. Separation of amino acid 2,4-dinitrophenyl-5-l-valine amide diastereomeric derivatives with high-performance planar chromatography and pressurized planar electrochromatography. JPC-J PLANAR CHROMAT 2013. [DOI: 10.1556/jpc.26.2013.2.13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Ilisz I, Aranyi A, Péter A. Chiral derivatizations applied for the separation of unusual amino acid enantiomers by liquid chromatography and related techniques. J Chromatogr A 2013; 1296:119-39. [PMID: 23598164 DOI: 10.1016/j.chroma.2013.03.034] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/14/2013] [Accepted: 03/14/2013] [Indexed: 12/25/2022]
Abstract
Amino acids are essential for life, and have many functions in metabolism. One particularly important function is to serve as the building blocks of peptides and proteins, giving rise complex three dimensional structures through disulfide bonds or crosslinked amino acids. Peptides are frequently cyclic and contain proteinogenic as well as nonproteinogenic amino acids in many instances. Since most of the proteinogenic α-amino acids contain at least one stereogenic center (with the exception of glycine), the stereoisomers of all these amino acids and the peptides in which they are to be found may possess differences in biological activity in living systems. The impetus for advances in chiral separation has been highest in the past 25 years and this still continues to be an area of high focus. The important analytical task of the separation of isomers is achieved mainly by chromatographic and electrophoretic methods. This paper reviews indirect separation approaches, i.e. derivatization reactions aimed at creating the basis for the chromatographic resolution of biologically and pharmaceutically important enantiomers of unusual amino acids and related compounds, with emphasis on the literature published from 1980s. The main aspects of the chiral derivatization of amino acids are discussed, i.e. derivatization on the amino group, transforming the molecules into covalently bonded diastereomeric derivatives through the use of homochiral derivatizing agents. The diastereomers formed (amides, urethanes, urea and thiourea derivatives, etc.) can be separated on achiral stationary phases. The applications are considered, and in some cases different derivatizing agents for the resolution of complex mixtures of proteinogenic d,l-amino acids, non-proteinogenic amino acids and peptides/amino acids from peptide syntheses or microorganisms are compared.
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Affiliation(s)
- István Ilisz
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary
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7
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Ilisz I, Aranyi A, Pataj Z, Péter A. Enantiomeric separation of nonproteinogenic amino acids by high-performance liquid chromatography. J Chromatogr A 2012; 1269:94-121. [DOI: 10.1016/j.chroma.2012.07.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/02/2012] [Accepted: 07/06/2012] [Indexed: 10/28/2022]
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8
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Ilisz I, Berkecz R, Péter A. Application of chiral derivatizing agents in the high-performance liquid chromatographic separation of amino acid enantiomers: A review. J Pharm Biomed Anal 2008; 47:1-15. [DOI: 10.1016/j.jpba.2007.12.013] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 12/06/2007] [Indexed: 10/22/2022]
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9
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Remsburg JW, Armstrong DW, Péter A, Tóth G. LC Enantiomeric Separation of Unusual Amino Acids Using Cyclodextrin‐based Stationary Phases. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070701738886] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Jeffrey W. Remsburg
- a Department of Chemistry and Biochemistry , University of Texas at Arlington , Arlington, Texas, USA
| | - Daniel W. Armstrong
- a Department of Chemistry and Biochemistry , University of Texas at Arlington , Arlington, Texas, USA
| | - Antal Péter
- b Department of Inorganic and Analytical Chemistry , University of Szeged , Szeged, Hungary
| | - Géza Tóth
- c Institute of Biochemistry, Biological Research Center , Szeged, Hungary
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Török R, Berkecz R, Péter A. Enantioseparation of phenylalanine analogs on a quinine-based anion-exchanger chiral stationary phase: Structure and temperature effects. J Sep Sci 2006; 29:2523-32. [PMID: 17154133 DOI: 10.1002/jssc.200600100] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Application of a cinchona alkaloid-based chiral anion-exchanger stationary phase for the direct high-performance liquid chromatographic enantioseparation of N-protected unusual phenylalanine analogs is reported. The N-benzyloxycarbonyl, N-3,5-dinitrobenzyloxycarbonyl, N-benzoyl and N-3,5-dinitrobenzoyl derivatives were well separable with high resolution. To achieve optimal separation of the enantiomers, the chromatographic conditions and temperature were varied. Linear van't Hoff plots were observed in the studied temperature range, 278-343 K, and the apparent changes in enthalpy, delta(deltaH degrees), entropy, delta(delta S degrees), and Gibbs free energy, delta(delta G degrees), were calculated. The values of the thermodynamic parameters depended on the nature of the N-acyl groups, on the structures of the compounds, and especially on the nature of the substituent on C3 of phenylalanine.
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Affiliation(s)
- Roland Török
- Department of Inorganic and Analytical Chemistry, University of Szeged, Szeged, Hungary
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11
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Czerwenka C, Lindner W. Stereoselective peptide analysis. Anal Bioanal Chem 2005; 382:599-638. [PMID: 15856198 DOI: 10.1007/s00216-005-3091-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Revised: 01/14/2005] [Accepted: 01/19/2005] [Indexed: 10/25/2022]
Abstract
The stereochemistry of a peptide determines its spatial features and can profoundly influence its chemical properties and biological activity. Thus, the analysis of the stereochemical properties of a peptide is an important aspect of its characterisation. For such investigations a "selector" that engages in stereoselective interactions with the peptide analytes is often used. A substantiated knowledge of the underlying molecular recognition mechanism will therefore be helpful in understanding existing and developing new stereoselective analysis systems. After a short introduction concerning the fundamentals of peptide stereoisomers and their biological implications, the stereoselective peptide analysis methods described in the literature are comprehensively reviewed. The characteristics and applications of the employed methods based on various techniques including chromatography (pressure- and electrokinetically driven), capillary electrophoresis, nuclear magnetic resonance spectroscopy and mass spectrometry are discussed. The various selectors that have been utilised to discriminate peptide enantiomers and/or diastereomers are described concurrently. The review concludes with an overview of combinations and comparisons of techniques that have been applied to the analysis of peptide stereoisomers and constitute a trend for further developments.
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Affiliation(s)
- Christoph Czerwenka
- Institute of Analytical Chemistry, University of Vienna, Währingerstrasse 38, 1090 Wien, Austria
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12
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Alı́as M, López MP, Cativiela C. An efficient and stereodivergent synthesis of threo- and erythro-β-methylphenylalanine. Resolution of each racemic pair by semipreparative HPLC. Tetrahedron 2004. [DOI: 10.1016/j.tet.2003.11.044] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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13
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Péter A, Árki A, Fülöp F. A Method to Study Column Efficiency in Indirect HPLC Enantioseparation. J LIQ CHROMATOGR R T 2004. [DOI: 10.1081/jlc-200034911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- A. Péter
- a Department of Inorganic and Analytical Chemistry , University of Szeged , Dóm tér 7, H‐6720 , Szeged , Hungary
| | - A. Árki
- a Department of Inorganic and Analytical Chemistry , University of Szeged , Dóm tér 7, H‐6720 , Szeged , Hungary
| | - F. Fülöp
- b Institute of Pharmaceutical Chemistry , University of Szeged , Szeged , Hungary
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14
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FERMIN BC, RADINSKY JA, KRATOCHVIL RJ, HALL JE, O YML. Integration of Rapid Derivatization and Gradient Elution Techniques for Enhanced High-Performance Liquid Chromatography Analysis of Key Amino Acids in Wheat Flour. J Food Sci 2003. [DOI: 10.1111/j.1365-2621.2003.tb05786.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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B'Hymer C, Montes-Bayon M, Caruso JA. Marfey's reagent: Past, present, and future uses of 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide. J Sep Sci 2003. [DOI: 10.1002/jssc.200390019] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Toyo'oka T. Resolution of chiral drugs by liquid chromatography based upon diastereomer formation with chiral derivatization reagents. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 2002; 54:25-56. [PMID: 12543490 DOI: 10.1016/s0165-022x(02)00127-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chiral derivatization reagents for resolution of biologically important compounds, such as chiral drugs by high-performance liquid chromatography (HPLC), based upon pre-column derivatization and diastereomer formation, are reviewed. The derivatization reagents for various functional groups, i.e., amine, carboxyl, carbonyl, hydroxyl and thiol, are evaluated in terms of reactivity, stability, wavelength, handling, versatility, sensitivity, and selectivity. The applicability of the reagents to the analyses of drugs and bioactive compounds are included in the text.
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Affiliation(s)
- Toshimasa Toyo'oka
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan.
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17
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Péter A, Vékes E, Armstrong DW. Effects of temperature on retention of chiral compounds on a ristocetin A chiral stationary phase. J Chromatogr A 2002; 958:89-107. [PMID: 12134834 DOI: 10.1016/s0021-9673(02)00390-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The isocratic retention of enantiomers of chiral analytes, i.e. tryptophan, 1,2,3,4-tetrahydroisoquinoline and gamma-butyrolac tone analogs, was studied on a ristocetin A chiral stationary phase at different temperatures and with different mobile phase compositions, using the reversed-phase, polar-organic and normal-phase modes. By variation of the both mobile phase composition and the temperature, baseline separations could be achieved for these enantiomers. The retention factors and selectivity factors for the enantiomers of all investigated compounds decreased with increasing temperature. The natural logarithms of the retention factors (ln k) of the investigated compounds depended linearly on the inverse of temperature (1/T). van't Hoff plots afforded thermodynamic parameters, such as the apparent change in enthalpy (deltaH(o)), the apparent change in entropy (deltaS(o)) and the apparent change in Gibbs free energy (deltaG(o) ) for the transfer of analyte from the mobile to the stationary phase. The thermodynamic parameters (deltaH(o), deltaS(o) and deltaG(o)) were calculated in order to promote an understanding of the thermodynamic driving forces for retention in this chromatographic system.
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Affiliation(s)
- Antal Péter
- Department of Inorganic and Analytical Chemistry, University of Szeged, Hungary.
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18
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Vékes E, Török G, Péter A, Sapi J, Tourwé D. Indirect high-performance liquid chromatographic separation of stereoisomers of beta-alkyl-substituted amino acids by the application of (S)-N-(4-nitrophenoxycarbonyl)phenylalanine methoxyethyl ester as chiral derivatizing agent. J Chromatogr A 2002; 949:125-39. [PMID: 11999729 DOI: 10.1016/s0021-9673(01)01455-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The indirect high-performance liquid chromatographic enantioresolution of beta-alkyl-substituted analogues of tyrosine, phenylalanine, 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid and tryptophan is reported. (S)-N-(4-Nitrophenoxycarbonyl)phenylalanine methoxyethyl ester, a recently developed chiral derivatizing agent, was used for pre-column derivatization of the investigated analytes. The diastereoisomers formed were analysed under reversed-phase conditions. The effects of parameters such as the amount and type of the organic modifier and the type of the stationary phase on the resolution and retention of the derivatives were investigated. Chromatographic conditions were found for the separation of all four stereoisomers of each analyte.
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Affiliation(s)
- Erika Vékes
- Department of Inorganic and Analytical Chemistry, University of Szeged, Hungary
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Grobuschek N, Schmid MG, Tuscher C, Ivanova M, Gübitz G. Chiral separation of beta-methyl-amino acids by ligand exchange using capillary electrophoresis and HPLC. J Pharm Biomed Anal 2002; 27:599-605. [PMID: 11755760 DOI: 10.1016/s0731-7085(01)00616-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This paper deals with the chiral separation of optical isomers of beta-methyl-amino acids by CE and HPLC using the principle of ligand-exchange. Capillary zone electrophoresis was carried out using Cu(II) complexes of L-4-hydroxyproline (L-4-Hypro), N-(2-hydroxypropyl)-L-4-hydroxyproline (HP-L-4-Hypro) and N-(2-hydroxyoctyl)-L-4-hydroxyproline (HO-L-4-Hypro) as chiral selectors, added to the electrolyte. The HPLC separations were performed on a chiral stationary ligand-exchange chromatography phase containing L-4-Hypro chemically bonded to silica gel. With both techniques nearly all compounds investigated are baseline resolved using different background electrolytes and mobile phases, respectively.
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Affiliation(s)
- N Grobuschek
- Institute of Pharmaceutical Chemistry, Karl-Franzens University, Graz, Austria
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20
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Sun XX, Sun LZ, Aboul-Enein HY. Chiral derivatization reagents for drug enantioseparation by high-performance liquid chromatography based upon pre-column derivatization and formation of diastereomers: enantioselectivity and related structure. Biomed Chromatogr 2001; 15:116-32. [PMID: 11268052 DOI: 10.1002/bmc.41] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Structures and related enantioselectivities of the respective chiral derivatization reagents (CDRs) for drug enantioseparation by high-performance chromatography based upon pre-column derivatization and diastereomeric formation are reviewed. The elution order of diastereomers caused reaction of some CDRs with enantiomeric amino acids and carboxylic acids. The development of new CDRs available for indirect HPLC methods is also discussed. (c) 2001 John Wiley & Sons, Ltd.
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Affiliation(s)
- X X Sun
- Department of Chemical Engineering, Jiangsu Institute of Petrochemical Technology, Changzhou 213016, People's Republic of China
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Péter A, Török G, Armstrong DW, Tóth G, Tourwé D. High-performance liquid chromatographic separation of enantiomers of synthetic amino acids on a ristocetin A chiral stationary phase. J Chromatogr A 2000; 904:1-15. [PMID: 11209895 DOI: 10.1016/s0021-9673(00)00917-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A macrocyclic glycopeptide, ristocetin A, was used as chiral stationary phase for the high-performance liquid chromatographic separation of enantiomers of 28 unnatural amino acids, such as analogues of phenylalanine, tyrosine and tryptophan, and analogues containing 1,2,3,4-tetrahydroisoquinoline, tetraline or 1,2,3,4-tetrahydro-2-carboline skeletons. Excellent resolutions were achieved for most of the investigated compounds by using reversed-phase or a new polar-organic mobile phase system. The conditions of separation were optimized by variation of the mobile phase composition, temperature and flow-rate.
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Affiliation(s)
- A Péter
- Department of Inorganic and Analytical Chemistry, University of Szeged, Hungary.
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22
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Péter A, Török G, Tóth G, Lindner W. Direct High-Performance Liquid Chromatographic Enantioseparation of β-Methyl-Substituted Unusual Amino Acids on a Quinine-Derived Chiral Anion-Exchange Stationary Phase. ACTA ACUST UNITED AC 2000. [DOI: 10.1002/1521-4168(20001101)23:11<628::aid-jhrc628>3.0.co;2-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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23
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Szabó S, Khlafulla R, Szarvas S, Almás M, Ladányi L, Szókán G. HPLC enantioseparation of amino acids and their protected derivatives used in peptide synthesis with pre-column chiral derivatization. Chromatographia 2000. [DOI: 10.1007/bf02492805] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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24
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Affiliation(s)
- D J Anderson
- Department of Chemistry, Cleveland State University, Ohio 44115, USA
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25
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Péter A, Török G, Armstrong DW, Tóth G, Tourwé D. Effect of temperature on retention of enantiomers of beta-methyl amino acids on a teicoplanin chiral stationary phase. J Chromatogr A 1998; 828:177-90. [PMID: 9916304 DOI: 10.1016/s0021-9673(98)00835-8] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The isocratic retention of enantiomers of beta-methyl amino acids (beta-methyltyrosine, beta-methylphenylalanine, beta-methyl-tryptophan and beta-methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) was studied on a teicoplanin-containing chiral stationary phase at different temperatures and at different mobile phase compositions, using the reversed-phase mode. With variation of both mobile phase composition and temperature, almost baseline separations could be achieved for all four enantiomers of sterically hindered amino acids. The retention factors and selectivity factors for the enantiomers of all investigated compounds decreased with increasing temperature. The natural logarithms of the retention factors (ln k) of the investigated compounds depended linearly on the inverse of temperature (1/T). van 't Hoff plots afforded thermodynamic parameters, such as the apparent change in enthalpy (delta H degree), the apparent change in entropy (delta S degree) and the apparent change in Gibbs free energy (delta G degree) for the transfer of analyte from the mobile to the stationary phase. The thermodynamic constants (delta H degree, delta S degree and delta G degree) were calculated in order to promote an understanding of the thermodynamic driving forces for retention in this chromatographic system.
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Affiliation(s)
- A Péter
- Department of Inorganic and Analytical Chemistry, Attila József University, Szeged, Hungary
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26
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High-performance liquid chromatographic separation of enantiomers of cyclic 1,3-amino alcohol derivatives. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(98)00471-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Dorsey JG, Cooper WT, Siles BA, Foley JP, Barth HG. Liquid Chromatography: Theory and Methodology. Anal Chem 1998. [DOI: 10.1021/a1980022h] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- John G. Dorsey
- Department of Chemistry, Florida State University, Tallahassee, Florida 32306-4390
| | - William T. Cooper
- Department of Chemistry, Florida State University, Tallahassee, Florida 32306-4390
| | - Barbara A. Siles
- Department of Chemistry, College of William and Mary, Williamsburg, Virginia 23187-8795
| | - Joe P. Foley
- Department of Chemistry, Villanova University, Villanova, Pennsylvania 19085-1699
| | - Howard G. Barth
- Central Research and Development Department, E. I. du Pont de Nemours & Company, P.O. Box 80228, Experimental Station, Wilmington, Delaware 19880
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