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Kandula JS, Rayala VVSPK, Parmar K, Ponnapalli VS, Gantala M, P R. Enantioselective polar-organic mode high-performance liquid chromatographic separation of lifitegrast on immobilized polysaccharide stationary phase and its application to pH-dependent chiral interconversion studies. Chirality 2024; 36:e23636. [PMID: 38384152 DOI: 10.1002/chir.23636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 02/23/2024]
Abstract
(S)-Lifitegrast (LFT) is the novel integrin antagonist, approved by the Food and drug administration, to treat signs and symptoms of dry eye disease. Synthesis of racemic LFT, preparative and analytical enantiomer separation, and chiral interconversion studies are lacking in the literature. Hence, in our study, synthesis of LFT racemate, chiral preparative purification procedure of enantiomer, and comprehensive analytical advancements are focused on rapid enantioselective separation and pH-dependent chiral interconversion studies. The synthesis of LFT racemate employed 2-amino-3-(3-(methylsulfonyl)phenyl)propanoic acid hydrochloride and 2-(benzofuran-6-carbonyl)-5,7-dichloro-1,2,3,4-tetrahydroisoquinoline-6-carbonyl chloride as starting materials. (R)-LFT was isolated from the racemate by preparative chiral HPLC and characterized using Q-TOF, FT-IR, NMR spectroscopy, and chiral HPLC. The purity of (R)-LFT was determined to have an enantiomeric excess of 99.12%. A precise, accurate, rapid HPLC-DAD enantioselective analytical method has been developed on Chiralpak IC [tris(3,5-dichloro phenyl carbamate) immobilized on cellulose] using water and methanol as mobile phase. The chiral interconversion study reveals 0.22% and 0.21% of interconversion of (S)-LFT into (R)-LFT at 80°C in pH 7.4 and 9.5 buffers, respectively, on the 24th day. An alternative route to enantioselective synthesis of LFT enantiomers by chromatographic separation is proposed. The validated enantioselective HPLC method will help to test the regular quality control samples.
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Affiliation(s)
- Jony Susanna Kandula
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research, Guwahati, Guwahati, Assam, India
| | | | - Keyur Parmar
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research, Guwahati, Guwahati, Assam, India
| | | | - Mahendar Gantala
- Daicel Chiral Technologies (India) Private Limited, Hyderabad, Telangana, India
| | - Radhakrishnanand P
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research, Guwahati, Guwahati, Assam, India
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2
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Wong YF, Kulsing C, Marriott PJ. Switchable Enantioselective Three- and Four-Dimensional Dynamic Gas Chromatography–Mass Spectrometry: Example Study of On-Column Molecular Interconversion. Anal Chem 2017; 89:5620-5628. [DOI: 10.1021/acs.analchem.7b00853] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yong Foo Wong
- Australian Centre for Research
on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Chadin Kulsing
- Australian Centre for Research
on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Philip J. Marriott
- Australian Centre for Research
on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
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3
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Evaluation of reversible interconversion in comprehensive two-dimensional gas chromatography using enantioselective columns in first and second dimensions. J Chromatogr A 2015; 1404:104-14. [DOI: 10.1016/j.chroma.2015.05.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/04/2015] [Accepted: 05/21/2015] [Indexed: 11/18/2022]
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4
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Supercritical fluid chromatography as a tool for enantioselective separation; A review. Anal Chim Acta 2014; 821:1-33. [DOI: 10.1016/j.aca.2014.02.036] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/31/2014] [Accepted: 02/22/2014] [Indexed: 12/14/2022]
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5
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Bu X, Skrdla P, Dormer P, Bereznitski Y. Separation of triphenyl atropisomers of a pharmaceutical compound on a novel mixed mode stationary phase: A case study involving dynamic chromatography, dynamic NMR and molecular modeling. J Chromatogr A 2010; 1217:7255-64. [DOI: 10.1016/j.chroma.2010.09.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 09/09/2010] [Accepted: 09/14/2010] [Indexed: 10/19/2022]
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6
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Trapp O. Investigation of the stereodynamics of molecules and catalyzed reactions by CE. Electrophoresis 2010; 31:786-813. [DOI: 10.1002/elps.200900599] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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7
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Mukherjee PS. Chiral interconversion monitoring of a drug candidate by supercritical fluid chromatography (SFC). J Pharm Biomed Anal 2009; 50:349-55. [DOI: 10.1016/j.jpba.2009.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 05/04/2009] [Accepted: 05/05/2009] [Indexed: 11/16/2022]
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8
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Cirilli R, Costi R, Di Santo R, La Torre F, Pierini M, Siani G. Perturbing Effects of Chiral Stationary Phase on Enantiomerization Second-Order Rate Constants Determined by Enantioselective Dynamic High-Performance Liquid Chromatography: A Practical Tool to Quantify the Accessible Acid and Basic Catalytic Sites Bonded on Chromatographic Supports. Anal Chem 2009; 81:3560-70. [DOI: 10.1021/ac802212s] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roberto Cirilli
- Dipartimento del Farmaco, Istituto Superiore di Sanità, Viale Regina Elena 299, I-00161 Rome, Italy, Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazzale A. Moro 5, I-00185 Rome, Italy, and Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, via dei Vestini 31-66013 Chieti, Italy
| | - Roberta Costi
- Dipartimento del Farmaco, Istituto Superiore di Sanità, Viale Regina Elena 299, I-00161 Rome, Italy, Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazzale A. Moro 5, I-00185 Rome, Italy, and Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, via dei Vestini 31-66013 Chieti, Italy
| | - Roberto Di Santo
- Dipartimento del Farmaco, Istituto Superiore di Sanità, Viale Regina Elena 299, I-00161 Rome, Italy, Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazzale A. Moro 5, I-00185 Rome, Italy, and Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, via dei Vestini 31-66013 Chieti, Italy
| | - Francesco La Torre
- Dipartimento del Farmaco, Istituto Superiore di Sanità, Viale Regina Elena 299, I-00161 Rome, Italy, Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazzale A. Moro 5, I-00185 Rome, Italy, and Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, via dei Vestini 31-66013 Chieti, Italy
| | - Marco Pierini
- Dipartimento del Farmaco, Istituto Superiore di Sanità, Viale Regina Elena 299, I-00161 Rome, Italy, Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazzale A. Moro 5, I-00185 Rome, Italy, and Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, via dei Vestini 31-66013 Chieti, Italy
| | - Gabriella Siani
- Dipartimento del Farmaco, Istituto Superiore di Sanità, Viale Regina Elena 299, I-00161 Rome, Italy, Istituto Pasteur Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, Piazzale A. Moro 5, I-00185 Rome, Italy, and Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, via dei Vestini 31-66013 Chieti, Italy
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9
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Krupčík J, Mydlová J, Májek P, Šimon P, Armstrong D. Methods for studying reaction kinetics in gas chromatography, exemplified by using the 1-chloro-2,2-dimethylaziridine interconversion reaction. J Chromatogr A 2008; 1186:144-60. [DOI: 10.1016/j.chroma.2008.01.028] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 01/02/2008] [Accepted: 01/11/2008] [Indexed: 11/16/2022]
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10
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Mydlová J, Krupcík J, Májek P, Skacáni I, Jakubík T, Sandra P, Armstrong DW. Gas chromatographic determination of the interconversion energy barrier for dialkyl 2,3-pentadienedioate enantiomers. J Chromatogr A 2007; 1150:124-30. [PMID: 17379233 DOI: 10.1016/j.chroma.2007.02.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 02/21/2007] [Accepted: 02/26/2007] [Indexed: 10/23/2022]
Abstract
The enantiomers of dialkyl 2,3-pentadienedioate undergo interconversion during gas chromatographic separation on chiral stationary phases. In this paper the on-column apparent interconversion kinetic and thermodynamic activation data were determined for dimethyl, diethyl, propylbutyl and dibutyl 2,3-pentadienedioate enantiomers by gas chromatographic separation of the racemic mixtures on a capillary column containing a polydimethylsiloxane stationary phase coupled to 2,3-di-O-methyl-6-O-tertbutyldimethylsilyl-beta-cyclodextrin. A deconvolution method was used to determine the individual enantiomer peak areas and retention times that are needed to calculate the interconversion rate constants and the energy barriers. The apparent rate constants and interconversion energy barriers decrease slightly with an increase in the alkyl chain length of the dialkyl 2,3-pentadienedioate esters. The optimum conformation of the dialkyl 2,3-pentadienedioate molecules, their separation selectivity factors and apparent interconversion enthalpy and entropy data changes with the alkyl chain length. The dependence of the apparent interconversion energy barrier (deltaG(app)(a-->b), deltaG(app)(b-->a)) on temperature was used to determine the apparent activation enthalpy (deltaH(app)(a-->b), deltaH(app)(b-->a)) and apparent entropy (deltaS(app)(a-->b), deltaS(app)(a-->b)) (where a denotes the first and b second eluted enantiomer). The comparison of the activation enthalpy and entropy (deltaS(app)(a-->b), deltaS(app)(a-->b)) indicated that the interconversion of dialkyl 2,3-pentadienedioate enantiomers on the HP-5+Chiraldex B-DM column series is an entropy driven process at 160 degrees C. Data obtained for dimethyl 2,3-pentadienedioate enantiomers on the HP-5+Chiraldex B-DM column series at 120 degrees C (deltaG(app)(a-->b) = 123.3 and deltaG(app)(b-->a) = 124.4 kJ mol(-1)) corresponds (at the 95% confidence interval) with the value of deltaG(#) = 128+/-1 kJ mol(-1) found at this temperature by gas chromatography using a two-dimensional stop flow technique on an empty capillary column [V. Schurig, F. Keller, S. Reich, M. Fluck, Tetrahedron: Asymmetry 8 (1997) 3475].
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Affiliation(s)
- J Mydlová
- Institute of Analytical Chemistry, Slovak University of Technology, Radlinského 9, Bratislava 81237, Slovakia
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11
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Fedurcová A, Lehotay J, Liptaj T, Prónayová N, Čižmárik J. HPLC Separation of Diazepam Conformers Coupled with Off‐Line NMR Experiment. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070600598852] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Andrea Fedurcová
- a Department of Analytical Chemistry, Faculty of Chemical and Food Technology , Slovak University of Technology , Bratislava, Slovakia
| | - Jozef Lehotay
- a Department of Analytical Chemistry, Faculty of Chemical and Food Technology , Slovak University of Technology , Bratislava, Slovakia
| | - Tibor Liptaj
- b Central Laboratory, Faculty of Chemical and Food Technology , Slovak University of Technology , Bratislava, Slovakia
| | - Nad'a Prónayová
- b Central Laboratory, Faculty of Chemical and Food Technology , Slovak University of Technology , Bratislava, Slovakia
| | - Jozef Čižmárik
- c Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Commenius University , Bratislava, Slovakia
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12
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Mydlová J, Fedurcová A, Lehotay J, Krupcík J, Májek P, Armstrong DW, He BL, Cotton FA. Determination of the interconversion energy barrier of 2,3-pentadienedioic acid enantiomers by HPLC. 2. On-column interconversion. J Sep Sci 2006; 29:2594-9. [PMID: 17313099 DOI: 10.1002/jssc.200600164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this paper, an HPLC method is used to determine the enantiomerization barrier of 2,3-pentadienedioic acid enantiomers. The racemate of 2,3-pentadienedioic acid was separated by HPLC on a chiral CHIROBIOTIC T column with a 90:10 (100:0.5:0.5 MeOH/HOAc/TEA)/H2O mobile phase. Peak areas of enantiomers prior to (A(+)0, A(-)0) and after the separation (A(+), A(-)), were used for calculation of the rate constants and the enantiomerization barrier, as determined by computer-assisted peak deconvolution of the peak clusters on the chromatograms. The kinetic equation for irreversible reactions was used to determine the apparent enantiomerization rate constants and the interconversion energy barrier. The dependence of the apparent enantiomerization barrier (deltaG1(app), deltaG-1(app)) on temperature was used to determine the apparent activation enthalpy (deltaH1(app), deltaH(-1)app) and entropy (deltaS1(app), deltaS-1(app)) for the interconversion of 2,3-pentadienedioic acid enantiomers, where the coefficients 1 and -1 designate the interconversions (+) --> (-) and (-) --> (+), respectively.
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Affiliation(s)
- Janka Mydlová
- Department of Analytical Chemistry, FCHFT Slovak University of Technology, Bratislava, Slovakia
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13
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Mydlová J, Krupcík J, Májek P, Skacáni I, Jakubík T, Armstrong DW. Gas chromatographic determination of the interconversion energy barrier for dimethyl-2,3-pentadienedioate enantiomers. J Sep Sci 2006; 29:1497-507. [PMID: 16894795 DOI: 10.1002/jssc.200600039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The enantiomers of dimethyl-2,3-pentadienedioate undergo interconversion during gas chromatographic separation on 2,6-di-O-methyl-3-O-pentyl-beta-, 2,6-di-O-methyl-3-O-pentyl-gamma-, and 2,3-di-O-methyl-6-O-tert butyldimethylsilyl-beta-CD chiral stationary phases. The combination of a deconvolution method with an internal standard was used to determine individual enantiomer peak areas and retention times needed for the calculation of the interconversion rate constants and the energy barrier for dimethyl-2,3-pentadienedioate enantiomers. The kinetic and thermodynamic data obtained for the interconversion data (rate constants, energy barriers, enthalpies, and entropies) were in good agreement with the published data (Trapp, O., Schurig, V., Chirality 2002, 14, 465-470) using permethylated-beta-CD (Chirasil-beta-Dex).
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Affiliation(s)
- Janka Mydlová
- Department of Analytical Chemistry, Slovak University of Technology, Bratislava, Slovakia
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14
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Trapp O. Unified Equation for Access to Rate Constants of First-Order Reactions in Dynamic and On-Column Reaction Chromatography. Anal Chem 2006; 78:189-98. [PMID: 16383327 DOI: 10.1021/ac051655r] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A unified equation to evaluate elution profiles of reversible as well as irreversible (pseudo-) first-order reactions in dynamic chromatography and on-column reaction chromatography has been derived. Rate constants k1 and k(-1) and Gibbs activation energies are directly obtained from the chromatographic parameters (retention times tR(A) and tR(B) of the interconverting or reacting species A and B, the peak widths at half-height wA and wB, and the relative plateau height h(p)), the initial amounts A0 and B0 of the reacting species, and the equilibrium constant K(A/B). The calculation of rate constants requires only a few iterative steps without the need of performing a computationally extensive simulation of elution profiles. The unified equation was validated by comparison with a data set of 125,000 simulated elution profiles to confirm the quality of this equation by statistical means and to predict the minimal experimental requirements. Surprisingly, the recovery rate from a defined data set is on average 35% higher using the unified equation compared to the evaluation by iterative computer simulation.
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Affiliation(s)
- O Trapp
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
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15
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Affiliation(s)
- T L Chester
- Procter & Gamble Company, Miami Valley Laboratories, 11810 East Miami River Road, Cincinnati, Ohio 45252, USA
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16
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Kiesswetter R, Brandl F, Kastner-Pustet N, Mannschreck A. Chiroptical detection during liquid chromatography: Deconvolution of overlapping peaks of enantiomers and its applications. Chirality 2003; 15 Suppl:S40-9. [PMID: 12884373 DOI: 10.1002/chir.10275] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The peaks of enantiomers in liquid chromatography (LC) frequently overlap for different reasons. The experimental curve can be deconvolved, i.e., transformed into the two curves of the enantiomers, without any assumption concerning their peak shapes. Besides the usual photometric UV detection, resulting in absorbance A, polarimetric or circular dichroic detection is required, providing the rotation 90 degree angle alpha or the differential absorbance DeltaA, respectively. The accuracy of the ratio alpha/A or DeltaA/A for the pure enantiomers is essential for the quality of the deconvolution. The determination of these ratios, using the overlapping peaks, and the subsequent computer deconvolution of the latter are discussed in more detail than in the earlier publications, e.g. Ref. 1 concerning this particular method. The computer program developed for this purpose is characterized. A condition is given which limits the availability of ratios and, therefore, the possibility of deconvolution. Several novel examples are described which stem from the following fields of application of deconvolved peaks: actual optical purities during LC (on-line analysis), overall optical purity of a sample, purities of chromatographic peaks, and, finally, enantiomerization during LC.
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Affiliation(s)
- Roland Kiesswetter
- Institut für Organische Chemie, Universität Regensburg, Regensburg, Germany
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Trapp O, Shellie R, Marriott P, Schurig V. Simulation of Elution Profiles for Two-Dimensional Dynamic Gas Chromatographic Experiments. Anal Chem 2003; 75:4452-61. [PMID: 14632049 DOI: 10.1021/ac0301144] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interconversion of E and Z isomers of acetaldoxime 1 and butyraldoxime 2 have been investigated by comprehensive two-dimensional dynamic gas chromatography (DGCxDGC) and computer simulation. Time-resolved cryogenic modulation is capable of revealing the precise isomeric ratio as a fine structure under the dynamic elution profile, which is characterized in one-dimensional experiments by a plateau formation or peak coalescence caused by interconversion of the isomers during the separation process. The chromatographic theoretical plate model has been extended for the computer simulation of comprehensive two-dimensional dynamic chromatographic experiments. A novel program, ChromWin 2D, based on the new algorithm has been developed for computer simulation to evaluate and predict the elution profiles of DGCxDGC experiments. ChromWin 2D allows the determination of rate constants and barriers of isomerization, epimerization, and enantiomerization processes occurring during chromatographic separations. The Eyring activation parameters of the E/Z and Z/E isomerization barriers in the presence of the stationary phase BP21 (poly(ethylene glycol) terephthalate terminated) were determined by temperature-dependent experiments between 80 and 90 degrees C for 1 and 70 and 130 degrees C for 2. The thermodynamic Gibbs free energy of the E/Z equilibrium of the isomers has been determined from the time-resolved chromatograms by cryogenic modulation. The method described here constitutes a new and important tool for the determination of isomerization barriers, which are of great interest, for example, for the quantitative determination of derivatized aldehydes, such as dinitrophenylhydrazine derivatives, in trace analysis.
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Affiliation(s)
- Oliver Trapp
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
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Krupcik J, Oswald P, Májek P, Sandra P, Armstrong W. Determination of the interconversion energy barrier of enantiomers by separation methods. J Chromatogr A 2003; 1000:779-800. [PMID: 12877200 DOI: 10.1016/s0021-9673(03)00238-3] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Separation methods have become versatile tools for the determination of kinetic activation parameters and energy barriers to interconversion of isomers and enantiomers in the last 20 years. New computer-aided evaluation systems allow the on-line determination of these data after separating minute amount of pure compounds or mixture of isomers or enantiomers, respectively. Both dynamic interconversion during the separation process as well as static stopped-flow techniques have been applied to determine the kinetic activation parameters and interconversion energy barriers by separation methods. The use of (1) combinations of batchwise kinetic studies with enantioselective separations, (2) a continuous flow model, (3) a comparison of real chromatograms with simulated ones, (4) stopped-flow techniques, (5) stochastic methods, (6) approximation functions and (7) deconvolution methods, for the determination of interconversion energy barriers by separation methods is summarized in detail.
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Affiliation(s)
- J Krupcik
- Department of Analytical Chemistry, Slovak University of Technology, Radlinského 9, Bratislava 81237, Slovakia.
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Oswald P, Desmet K, Sandra P, Krupcík J, Májek P, Armstrong DW. Determination of the enantiomerization energy barrier of some 3-hydroxy-1,4-benzodiazepine drugs by supercritical fluid chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 779:283-95. [PMID: 12361742 DOI: 10.1016/s1570-0232(02)00396-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The first-order kinetic equation for irreversible reactions was used to determine the enantiomerization barrier of some of 3-hydroxy-1,4-benzodiazepine enantiomers by supercritical fluid chromatography (SFC). The racemates of lorazepam, oxazepam and temazepam were separated by SFC on chiral (R,R)-Whelk-O1 column with supercritical carbon dioxide containing 12.5% methanol and 0.5% diethylamine as a mobile phase. Peak areas of enantiomers prior to (A(A0), A(B0)) and after the separation (A(A), A(B)), used for calculation of the enantiomerization barrier, were determined by computer-assisted peak deconvolution of peak clusters from the chromatograms. It was demonstrated for the first time that using a model for a four-peak cluster produces height precise results, and most closely approximates the published results. The kinetic equation for irreversible reactions was used to determine apparent enantiomerization rate constants. The dependence of the apparent enatiomerization barrier (deltaG(app)(A-->B), deltaG(app)(B-->A)) on temperature was used to determine apparent activation enthalpy (deltaH(app)(R-->S), deltaH(app)(S-->R)) and entropy (deltaS(app)(R-->S), deltaS(app)(S-->R)) for all studied benzodiazepines.
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Affiliation(s)
- Peter Oswald
- Department of Analytical Chemistry, Slovak University of Technology, Radlinského 9, Bratislava 81237, Slovakia
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