1
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Byrnes NA, Wu Y, Nolvachai Y, Marriott PJ. Exploring thermal isomerisation in gas chromatography analyses using natural pyrethrins: Comparison of comprehensive two-dimensional and one-dimensional gas chromatography. J Chromatogr A 2023; 1708:464369. [PMID: 37714012 DOI: 10.1016/j.chroma.2023.464369] [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: 07/31/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/17/2023]
Abstract
This study aims to assess and qualitatively compare the visual presentation of chromatographic data from the isomerisation of natural pyrethrins - a group of pesticides derived from Chrysanthemum flowers - using one-dimensional gas chromatography (1DGC) and comprehensive two-dimensional gas chromatography (GC×GC). Molecular structural changes, such as thermal isomerisation in this case, occur during gas chromatography injection and separation, to provide characteristic patterns which may not be routinely recognised on the 1D chromatogram. To demonstrate the influence of analytical method parameters on isomerisation processes, variations in oven temperature (isothermal vs. temperature programmed analysis), inlet mode (split vs. splitless), inlet temperature, and carrier gas flow rate were investigated. Increasing oven temperature was the most significant factor affecting isomerisation. Splitless injection mode and increasing inlet temperature promoted isopyrethrin formation, while the effect of inlet temperature appeared minimal with a split injection technique, most likely due to the short residence time in the inlet. Increased carrier gas flow rates in a temperature programmed analysis reduced retention time and minimised isomerisation. The unique presentation of isopyrethrin peaks on a GC×GC contour plot allows for facile recognition of isomerisation especially at low concentrations, simplifies chromatogram interpretation, and aids in analyte identification. It also confirms that the isomerisation process is irreversible since the pyrethrin I and II compounds are absent throughout the bridge formation. These benefits support the use of GC×GC over 1DGC to study isomerisation. Additionally, due to limited data in the literature, Kováts retention indices and linear retention indices of the natural pyrethrins, including isopyrethrins, were experimentally determined on four columns: DB-5 ms UI, Rxi-17Sil MS, SLB-IL60i, and SLB-IL111i.
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Affiliation(s)
- Neil Andrew Byrnes
- Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Yuesong Wu
- Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - Yada Nolvachai
- Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, VIC 3800, Australia; CASS Food Research Centre, School of Exercise and Nutritional Sciences, Faculty of Health, Deakin University, Burwood, VIC 3125, Australia
| | - Philip J Marriott
- Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, VIC 3800, Australia.
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2
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Du X, Zhang S, Wang L, Wang Y, Fan P, Jia W, Zhang P, Huang S. Single-Molecule Interconversion between Chiral Configurations of Boronate Esters Observed in a Nanoreactor. ACS NANO 2023; 17:2881-2892. [PMID: 36655995 DOI: 10.1021/acsnano.2c11286] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Isomers of some chemical compounds may be dynamically interconvertible. Due to a lack of sensing methods with a sufficient resolution, however, direct monitoring of such processes can be difficult. Engineered Mycobacterium smegmatis porin A (MspA) nanopores can be applied as nanoreactors so that chemical reactions can be directly monitored. Here, an MspA modified with a phenylboronic acid (PBA) adapter was prepared and was used to observe dynamic interconversion between chiral configurations of boronate esters, which appears as telegraphic switching on top of nanopore events. The mechanism of this behavior was further confirmed by trials with different halogenated catechols, dopamine, adenosine, 1,2-propanediol, and (2R,3R)-2,3-butanediol, and its generality has been demonstrated. These results suggest that an engineered MspA possesses an exceptional resolution in its monitoring of chemical reaction processes and may inspire the future design of nanopore small-molecule sensors.
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Affiliation(s)
- Xiaoyu Du
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023Nanjing, China
| | - Shanyu Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023Nanjing, China
| | - Liying Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023Nanjing, China
| | - Yuqin Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023Nanjing, China
| | - Pingping Fan
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023Nanjing, China
| | - Wendong Jia
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023Nanjing, China
| | - Panke Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023Nanjing, China
| | - Shuo Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023Nanjing, China
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3
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Multidimensional gas chromatography investigation of concentration and temperature effects of oxime interconversion on ionic liquid and poly(ethylene glycol) stationary phases. Anal Chim Acta 2019; 1081:200-208. [DOI: 10.1016/j.aca.2019.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/01/2019] [Accepted: 07/07/2019] [Indexed: 01/22/2023]
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4
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Zavahir JS, Nolvachai Y, Wood BR, Marriott PJ. Gas chromatography-Fourier transform infrared spectroscopy reveals dynamic molecular interconversion of oximes. Analyst 2019; 144:4803-4812. [PMID: 31276125 DOI: 10.1039/c9an00990f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study reports gas chromatography (GC) combined with Fourier transform infrared (FTIR) spectroscopy to investigate the elution profiles of individual oxime isomers undergoing characteristic interconversion (dynamic chromatography) in GC. The use of a light-pipe FTIR interface enables on-line acquisition of FTIR spectra, which in turn render unambiguous identification of the individual molecules. Here, acetaldehyde oxime and propionaldehyde oxime were chosen for comparison of elution behaviour under varying temperature and carrier flow velocities. The choice of selective responses (wavenumber selectivity), which were relatively stronger for each isomer, enabled display and retracing of the individual isomer over the chromatographic time scale and thus provided characteristic single isomer profiles. Chemometric data analysis using the multivariate curve resolution technique further confirmed this isomer elution profile. Simulation of the spectrum for each isomer allowed comparison with instrument-generated FTIR spectra to confirm the elution order of E and Z isomers. The effect of changing chromatographic parameters (temperature, flow) on interconversion rates and/or extents were studied and the corresponding change in FTIR spectrum intensity was noted. The GC-FID data acquired concurrently with GC-FTIR analyses ratified isomerisation chromatographic profiles.
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Affiliation(s)
- J Shezmin Zavahir
- Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, VIC 3800, Melbourne, Australia.
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5
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Haas M, Lamour S, Trapp O. Development of an advanced derivatization protocol for the unambiguous identification of monosaccharides in complex mixtures by gas and liquid chromatography. J Chromatogr A 2018; 1568:160-167. [PMID: 30122163 DOI: 10.1016/j.chroma.2018.07.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/23/2018] [Accepted: 07/04/2018] [Indexed: 11/16/2022]
Abstract
The separation and analysis of complex monosaccharide mixtures is highly challenging and requires typically carefully selected derivatization procedures to avoid changes in the sample composition. Here we present in a comparative study several single- and two-step derivatization approaches for LC and GC separations using a set of reference compounds ranging from C1 building block such as formaldehyde to C6 monosaccharides. Separation conditions have been optimized resulting in the simultaneous separation of 15 unbranched aldoses. By parallel derivatization using hydroxylamine hydrochloride (HACl)/ N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and O-ethylhydroxylamine hydrochloride (EtOx)/ N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and comparative GC measurements we developed a protocol for the unambiguous identification and separation of aldoses, ketoses, alditols and aldonic acids, which commonly occur in complex sugar mixtures as reaction by-products or decomposition products. In particular this procedure helps to deconvolute overlapping analytes and facilitates quantification. Additionally, the method presented here has been investigated in regard to storage life, detection limits, quantification and MS analysis. The broad applicability of this method to different sample matrices is shown for the analysis of food samples and complex aldol reaction mixtures in the formose reaction, which is of great relevance in the context of the origin of life.
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Affiliation(s)
- Maren Haas
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany; Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
| | - Saskia Lamour
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany; Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
| | - Oliver Trapp
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany; Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany.
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6
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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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7
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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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8
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Peak-bridges due to in-column analyte transformations as a new tool for establishing molecular connectivities by comprehensive two-dimensional gas chromatography–mass spectrometry. J Chromatogr A 2015; 1383:134-43. [DOI: 10.1016/j.chroma.2015.01.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/08/2014] [Accepted: 01/11/2015] [Indexed: 11/19/2022]
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9
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Shinde Y, Salunke-Gawali S. Reversed phase chromatographic separation and isolation of tautomers of naphthoquinoneoximes by HPLC. Effect of ph of mobile phase on separation of 3-chloro-2-hydroxy-4-naphthoquinone-1-oxime. JOURNAL OF ANALYTICAL CHEMISTRY 2014. [DOI: 10.1134/s1061934814120144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Chin ST, Marriott PJ. Multidimensional gas chromatography beyond simple volatiles separation. Chem Commun (Camb) 2014; 50:8819-33. [DOI: 10.1039/c4cc02018a] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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11
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SHINDE YOGESH, SPROULES STEPHEN, KATHAWATE LAXMI, PAL SANJIMA, KONKIMALLA VBADIREENATH, SALUNKE-GAWALI SUNITA. Separation and isolation of tautomers of 2-hydroxy-4-naphthoquinone-1-oxime derivatives by liquid chromatography: Antiproliferative activity and DFT studies. J CHEM SCI 2014. [DOI: 10.1007/s12039-013-0549-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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12
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Chromatographic peak deconvolution of constitutional isomers by multiple-reaction-monitoring mass spectrometry. J Chromatogr A 2010; 1217:1010-6. [DOI: 10.1016/j.chroma.2009.09.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 09/11/2009] [Accepted: 09/17/2009] [Indexed: 11/21/2022]
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13
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Chifuntwe C, Zhu F, Huegel H, Marriott PJ. Dynamic interconversion of chiral oxime compounds in gas chromatography. J Chromatogr A 2010; 1217:1114-25. [DOI: 10.1016/j.chroma.2009.11.084] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 11/23/2009] [Accepted: 11/25/2009] [Indexed: 12/01/2022]
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14
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Cirilli R, Ferretti R, De Santis E, Gallinella B, Zanitti L, La Torre F. High-performance liquid chromatography separation of enantiomers of flavanone and 2′-hydroxychalcone under reversed-phase conditions. J Chromatogr A 2008; 1190:95-101. [DOI: 10.1016/j.chroma.2008.02.101] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 02/21/2008] [Accepted: 02/25/2008] [Indexed: 10/22/2022]
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15
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Cirilli R, Ferretti R, La Torre F, Secci D, Bolasco A, Carradori S, Pierini M. High-performance liquid chromatographic separation of enantiomers and diastereomers of 2-methylcyclohexanone thiosemicarbazone, and determination of absolute configuration and configurational stability. J Chromatogr A 2007; 1172:160-9. [PMID: 17959189 DOI: 10.1016/j.chroma.2007.10.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 09/12/2007] [Accepted: 10/02/2007] [Indexed: 10/22/2022]
Abstract
Simultaneous HPLC diastereo- and enantioseparations of 2-methylcyclohexanone thiosemicarbazone (2-MCET) were accomplished on coated- and immobilized type polysaccharide-based chiral stationary phases (CSPs). The identification of all stereoisomeric forms and their stereochemistry were achieved by combining theoretical, HPLC and chiroptical data. The stereochemical stability of the target compound was studied by classical off-column and dynamic HPLC kinetic procedures and the influence of different parameters such solvent, TFA concentration and temperature on stereoisomerization process was evaluated. The findings obtained by chromatographic and kinetic experiments were used to develop a simple method to convert the racemic form of 2-MCET into a single enantiomer.
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Affiliation(s)
- R Cirilli
- Istituto Superiore di Sanità, Dipartimento del Farmaco, Viale Regina Elena 299, 00161 Rome, Italy.
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16
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Edris AE, Chizzola R, Franz C. Isolation and characterization of the volatile aroma compounds from the concrete headspace and the absolute of Jasminum sambac (L.) Ait. (Oleaceae) flowers grown in Egypt. Eur Food Res Technol 2007. [DOI: 10.1007/s00217-007-0623-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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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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18
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Adahchour M, Beens J, Vreuls R, Brinkman U. Recent developments in comprehensive two-dimensional gas chromatography (GC×GC). Trends Analyt Chem 2006. [DOI: 10.1016/j.trac.2006.03.002] [Citation(s) in RCA: 227] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Marriott PJ, Massil T, Hügel H. Molecular structure retention relationships in comprehensive two-dimensional gas chromatography. J Sep Sci 2004; 27:1273-84. [PMID: 15587276 DOI: 10.1002/jssc.200401917] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Comprehensive two-dimensional gas chromatography (GC x GC) offers new opportunities to develop relationships between molecular structure and retentions in the two dimensional (2D) separation space defined by the GC x GC retention in each dimension. Whereas single dimension GC provides only one retention property for a solute, and hence the specific relationship between retention and chemical property is not readily apparent or derivable, the 2D presentation of compounds in GC x GC provides a subtle and exquisite correlation of chemical property and retention unlike any other GC experiment. The 'orthogonality' of the two separation dimensions is intimately related to the manner in which different separation mechanisms, available through use of two dissimilar phases, are accessible to the different chemical compounds or classes in a sample mixture, and indeed the specific chemical classes present in the sample. The GC x GC experiment now permits various processes such as chemical decompositions, molecular interconversions, various non-linear chromatography effects, and processes such as slow reversible interactions that may arise with stationary phases or in the injector or column couplings, to be identified and further investigated. Here, we briefly review implementation of the GC x GC method, consider the molecular selectivity of GC x GC, and highlight a selection of molecular processes that can be probed by using GC x GC.
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Affiliation(s)
- Philip J Marriott
- Australian Centre for Research on Separation Science, School of Applied Sciences, RMIT University, Melbourne 3001, Australia.
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20
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Trapp O. Evaluation and Prediction of Stereoisomerizations in Comprehensive Two-Dimensional Chromatography. ACTA ACUST UNITED AC 2004; 44:1671-9. [PMID: 15446825 DOI: 10.1021/ci049899k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Conformational and configurational changes such as isomerizations, epimerizations, diastereomerizations and, enantiomerizations are important for the investigation of a large variety of processes ranging from protein folding to the stereostability of drugs. Under optimized conditions, these processes lead to an elution profile characterized by a plateau formation between the two interconverting species in chromatographic separations in a certain temperature range. By temperature-dependent measurements and subsequent computer simulation of the experimental chromatograms, the forward and backward rate constants k1 and k(-1), the Gibb's energy DeltaG++, activation enthalpy DeltaH++, and entropy DeltaS++ can be obtained. Due to its high efficiency two-dimensional chromatography is able to resolve the time-dependent distribution of the two species in the second dimension, thereby yielding the precise ratio of stereoisomers. An algorithm for the simulation and evaluation of two-dimensional chromatographic experiments has been developed, based on the theoretical plate model, which allows the determination of rate constants and barriers of isomerization, epimerization, and enantiomerization processes from two-dimensional chromatographic experiments. In the present article a detailed description of the extended theoretical plate model required for the simulation, the methods available, and examples for the evaluation of complex experimental data and the prediction of the separation conditions to observe isomerization, epimerizations, and enantiomerizations in two-dimensional chromatography are given.
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Affiliation(s)
- O Trapp
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
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21
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Joulain D, Casazza A, Laurent R, Portier D, Guillamon N, Pandya R, Le M, Viljoen A. Volatile flavor constituents of fruits from Southern Africa: Mobola plum (Parinari curatellifolia). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2004; 52:2322-5. [PMID: 15080640 DOI: 10.1021/jf030702i] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The volatile flavor components of Mobola plum (Parinari curatellifolia), a native fruit of Southern Africa, have been isolated by a vacuum headspace concentration method. The concentrate was analyzed by hyphenated gas chromatographic techniques, including gas chromatography (GC)/mass spectrometry (MS) and GC/Fourier transform infrared (FTIR), together with other GC-coupled detection devices for the specific and selective detection of nitrogen- and sulfur-containing compounds. A total of 88 components were identified. Of these compounds, 12 contain nitrogen, including 2-aminobenzaldehyde and phenylacetaldoxime, which are detected for the first time in an edible fruit. In addition, two unusual nitrated compounds have been identified, including optically active (2-nitrobutyl)benzene, which is a new natural product. Quantitative and sensory data of the new compounds are provided.
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Affiliation(s)
- Daniel Joulain
- Research Division, Robertet S A, BP 52100, F-06131 Grasse Cedex, France.
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22
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Marriott P, Aryusuk K, Shellie R, Ryan D, Krisnangkura K, Schurig V, Trapp O. Molecular interconversion behaviour in comprehensive two-dimensional gas chromatography. J Chromatogr A 2004; 1033:135-43. [PMID: 15072298 DOI: 10.1016/j.chroma.2004.01.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Comprehensive two-dimensional gas chromatography (GC x GC) is shown to provide information on dynamic molecular behaviour (interconversion), with the interconversion process occurring on both columns in the coupled-column experiment. The experiment requires suitable adjustment of both experimental conditions and relative dimensions of each of the columns. In this case, a longer column than normally employed in GC x GC allows sufficient retention duration on the second column, which permits the typical plateau-shape recognised for the interconversion process to be observed. The extent of interconversion depends on prevailing temperature, retention time, and the phase type. Polyethylene glycol-based phases were found to result in high interconversion kinetics, although terephthalic acid-terminated polyethylene glycol had a lesser extent of interconversion. Much less interconversion was seen for phenyl-methylpolysiloxane and cyclodextrin phases. This suggests that for the oximes, interconversion largely occurs in the stationary phase. Examples of different extents of interconversion in both dimensions are shown, including peak coalescence on the first column with little interconversion on the second column.
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Affiliation(s)
- Philip Marriott
- Department of Applied Chemistry, Australian Centre for Research on Separation Science, RMIT University, City Campus, GPO Box 2476V, Melbourne, Vic. 3001, Australia.
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23
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Górecki T, Harynuk J, Panić O. The evolution of comprehensive two-dimensional gas chromatography (GC×GC). J Sep Sci 2004; 27:359-79. [PMID: 15335072 DOI: 10.1002/jssc.200301650] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
For a technology little over a decade old, comprehensive two-dimensional gas chromatography (GC x GC) has quickly reached the status of one of the most powerful analytical tools for volatile organic compounds. At the heart of any GC x GC system is an interface, which physically connects the primary and the secondary columns and acts to preserve the separation obtained in the first dimension (first column) while allowing additional separation in the second dimension. The paper presents a review of the technology, including fundamental principles of the technique, data processing and interpretation and a timeline of inventive contributions to interface design. In addition, applications of the technique are presented, with a more detailed discussion of selected examples.
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Affiliation(s)
- Tadeusz Górecki
- Department of Chemistry, University of Waterloo, Ontario, Canada.
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24
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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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Dugave C, Demange L. Cis-trans isomerization of organic molecules and biomolecules: implications and applications. Chem Rev 2003; 103:2475-532. [PMID: 12848578 DOI: 10.1021/cr0104375] [Citation(s) in RCA: 753] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Christophe Dugave
- CEA/Saclay, Département d'Ingénierie et d'Etudes des Protéines (DIEP), Bâtiment 152, 91191 Gif-sur-Yvette, France.
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Dallüge J, Beens J, Brinkman UAT. Comprehensive two-dimensional gas chromatography: a powerful and versatile analytical tool. J Chromatogr A 2003; 1000:69-108. [PMID: 12877167 DOI: 10.1016/s0021-9673(03)00242-5] [Citation(s) in RCA: 348] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Comprehensive two-dimensional gas chromatography (GC x GC) is a novel technique which is rapidly gaining importance for the analysis of complex samples. In the present review, attention is devoted to the principle and advantages, and main characteristics such as modulation, column combinations, detector requirements and data processing, of the technique. Specifically, GC x GC of a variety of real-life samples is discussed to demonstrate the applicability of the technique, with emphasis on the usefulness of the ordered-structure principle and on the analyte-identification power provided by a combination with time-of-flight mass spectrometric detection.
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Affiliation(s)
- Jens Dallüge
- Vrije Universiteit, Department of Analytical Chemistry and Applied Spectroscopy, de Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
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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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Kallio M, Hyötyläinen T, Jussila M, Hartonen K, Palonen S, Shimmo M, Riekkola ML. Semi-rotating cryogenic modulator for comprehensive two-dimensional gas chromatography. Anal Bioanal Chem 2003; 375:725-31. [PMID: 12664170 DOI: 10.1007/s00216-003-1803-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2002] [Revised: 01/02/2003] [Accepted: 01/16/2003] [Indexed: 10/20/2022]
Abstract
A laboratory-made cryogenic modulator for comprehensive two-dimensional gas chromatography (GCxGC) was constructed and evaluated. Analytes were trapped with carbon dioxide and desorbed with heated GC oven air. The GCxGC system included a non-polar first-dimension column and a semi-polar second-dimension column connected to a flame ionisation detector. A laboratory-written Matlab-based program was used for the data analysis. Peak widths at half height for n-alkanes, obtained with use of new modulator, were at narrowest 60 ms.
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Affiliation(s)
- Minna Kallio
- Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, 00014 Helsinki, Finland
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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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Oswald P, Desmet K, Sandra P, Krupcik J, Armstrong DW. Evaluation of reversible and irreversible models for the determination of the enantiomerization energy barrier for N-(p-methoxybenzyl)-1,3,2-benzodithiazol-1-oxide by supercritical fluid chromatography. Chirality 2002; 14:334-9. [PMID: 11968075 DOI: 10.1002/chir.10077] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It has been found that the interconversion of enantiomers on a chromatographic column during the separation process can be studied by the first-order kinetic equations derived both for reversible and irreversible reactions in a stationary system if the extent of interconversion is not too high. The equation derived for irreversible reactions gives, however, results also for higher degrees of enantiomerization while that derived for reversible interconversion failed. The irreversible equation was used to determine the enantiomerization barrier of N-(p-methoxybenzyl)-l,3,2-benzodithiazol-l-oxide enantiomers by supercritical fluid chromatography. The racemate of N-(p-methoxybenzyl)-l,3,2-benzodithiazol-l-oxide was separated by supercritical fluid chromatography on the (R,R)-Whelk-Ol column with supercritical carbon dioxide containing 20% methanol as a mobile phase. Peak areas of enantiomers prior to and after the separation used for the calculation of the enantiomerization barrier were determined by computer-assisted peak deconvolution of peak clusters registered on chromatograms using commercial software.
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Affiliation(s)
- P Oswald
- Department of Analytical Chemistry, Slovak University of Technology, Bratislava 81237, Slovakia
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