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Betzenbichler G, Huber L, Kräh S, Morkos MLK, Siegle AF, Trapp O. Chiral stationary phases and applications in gas chromatography. Chirality 2022; 34:732-759. [PMID: 35315953 DOI: 10.1002/chir.23427] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/15/2022]
Abstract
Chiral compounds are ubiquitous in nature and play a pivotal role in biochemical processes, in chiroptical materials and applications, and as chiral drugs. The analysis and determination of the enantiomeric ratio (er) of chiral compounds is of enormous scientific, industrial, and economic importance. Chiral separation techniques and methods have become indispensable tools to separate chiral compounds into their enantiomers on an analytical as well on a preparative level to obtain enantiopure compounds. Chiral gas chromatography and high-performance liquid chromatography have paved the way and fostered several research areas, that is, asymmetric synthesis and catalysis in organic, medicinal, pharmaceutical, and supramolecular chemistry. The development of highly enantioselective chiral stationary phases was essential. In particular, the elucidation and understanding of the underlying enantioselective supramolecular separation mechanisms led to the design of new chiral stationary phases. This review article focuses on the development of chiral stationary phases for gas chromatography. The fundamental mechanisms of the recognition and separation of enantiomers and the selectors and chiral stationary phases used in chiral gas chromatography are presented. An overview over syntheses and applications of these chiral stationary phases is presented as a practical guidance for enantioselective separation of chiral compound classes and substances by gas chromatography.
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Affiliation(s)
| | - Laura Huber
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Sabrina Kräh
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | | | - Alexander F Siegle
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Oliver Trapp
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
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Grachev MK, Kurochkina GI, Popkov AV. The features of synthesis and chemical behavior of some silicon-containing cyclodextrin derivatives. Russ Chem Bull 2019. [DOI: 10.1007/s11172-019-2477-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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3
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Chiral Separations Using a Modified Water Stationary Phase in Supercritical Fluid Chromatography. Chromatographia 2018. [DOI: 10.1007/s10337-018-3534-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Grachev MK, Kurochkina GI, Levina II, Popkov AV. Silylation of β-cyclodextrin by various chlorosilanes. PHOSPHORUS SULFUR 2017. [DOI: 10.1080/10426507.2017.1354214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- M. K. Grachev
- Biology and Chemistry Institution of Moscow State University of Education, Moscow, Russian Federation
| | - G. I. Kurochkina
- Biology and Chemistry Institution of Moscow State University of Education, Moscow, Russian Federation
| | - I. I. Levina
- N.M.Emanuel Institution of Biochemical Physics of Russian Academy of Sciences, Moscow, Russian Federation
| | - A. V. Popkov
- Biology and Chemistry Institution of Moscow State University of Education, Moscow, Russian Federation
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Grachev MK, Popkov AV, Levina II, Kurochkina GI. Silylation of 2-hydroxypropyl-β-cyclodextrin. RUSS J GEN CHEM+ 2017. [DOI: 10.1134/s1070363217070155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Eibler D, Vetter W. Enantioseparation and optical rotation of flavor-relevant 4-alkyl-branched fatty acids. J Chromatogr A 2017; 1505:87-95. [DOI: 10.1016/j.chroma.2017.05.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 11/16/2022]
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7
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Kurochkina GI, Popkov AV, Levina II, Grachev MK. Synthesis of per-6-О-(tert-butyl)(diphenyl)silyl-β-cyclodextrin. RUSS J GEN CHEM+ 2016. [DOI: 10.1134/s1070363216020195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kaffarnik S, Heid C, Kayademir Y, Eibler D, Vetter W. High enantiomeric excess of the flavor relevant 4-alkyl-branched Fatty acids in milk fat and subcutaneous adipose tissue of sheep and goat. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:469-475. [PMID: 25544157 DOI: 10.1021/jf505452u] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Volatile 4-alkyl-branched fatty acids are characteristic flavor compounds of sheep and goat. Due to the methyl branch, the carbon C-4 represents a stereogenic center with the possible presence of one or both enantiomers in the respective samples. In this study, we used enantioselective gas chromatography to study the enantiomeric composition of 4-methyloctanoic acid (4-Me-8:0) and 4-ethyloctanoic acid (4-Et-8:0) in milk and dairy products from sheep and goat as well as in goat subcutaneous tissue. Different columns coated with modified cyclodextrins were tested to resolve racemic 4-alkyl-branched fatty acid methyl ester standards. The best enantiomer resolution was obtained on 25% octakis(2,3,6-tri-O-ethyl)-γ-cyclodextrin (γ-TECD) diluted in OV-1701. For analysis of the food samples, the lipids were extracted and fatty acids in the extracts were converted into fatty acid methyl esters. Non-aqueous reversed-phase high-performance liquid chromatography was used to fractionate the samples in order to gain one solution enriched in 4-Me-8:0 methyl ester and one solution enriched with 4-Et-8:0 methyl ester. Subsequent analysis by enantioselective gas chromatography with mass spectrometry allowed only the detection of one enantiomer of 4-Me-8:0 and 4-Et-8:0 in the samples. By means of a non-racemic standard of 4-Me-8:0, it was found that the predominant enantiomer was (R)-4-Me-8:0.
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Affiliation(s)
- Stefanie Kaffarnik
- University of Hohenheim , Institute of Food Chemistry (170b), Garbenstraße 28, 70593 Stuttgart, Germany
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Zawatzky K, Kamuf M, Trapp O. Chiral 1,2-dialkenyl diaziridines: synthesis, enantioselective separation, and nitrogen inversion barriers. Chirality 2014; 27:156-62. [PMID: 25378198 DOI: 10.1002/chir.22405] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/12/2014] [Indexed: 11/09/2022]
Abstract
trans-1,2-Disubstituted diaziridines form stable enantiomers at ambient conditions because of the two stereogenic pyramidal nitrogen atoms. Functionalized trans-1,2-disubstituted diaziridines can be utilized as a chiral switching moiety between two enantiomeric states in more complex molecular structures. However, the synthesis of functionalized diaziridines is quite challenging, because of the limited tolerance of reaction conditions that can be applied. Here we present a strategy to make trans-1,2-disubstituted diaziridines accessible as versatile building blocks in C-C-bond formations, i.e., the Heck reaction, and therefore introducing aryl substituents. The synthesis of trans-1,2-dialkenyl diaziridines with terminal alkenyl substituents and their stereodynamic properties are described.
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Affiliation(s)
- Kerstin Zawatzky
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
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Kamuf M, Trapp O. Stereodynamics of tetramezine. Chirality 2010; 23:113-7. [PMID: 20845424 DOI: 10.1002/chir.20885] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 06/02/2010] [Indexed: 11/05/2022]
Abstract
The antidepressant drug tetramezine [1,2-bis-(3,3-dimethyldiaziridin-1-yl)ethane] consists of two bridged diaziridine moieties with four stereogenic nitrogen centers, which are stereolabile and, therefore, are prone to interconversion. The adjacent substituents at the nitrogen atoms of the diaziridines moieties exist only in an antiperiplanar conformation, which results in a coupled interconversion. Therefore, three stereoisomers exist (meso form and two enantiomeric forms), which epimerize when the diaziridine moieties are regarded as stereogenic units due to the coupled interconversion. Here, we have investigated the epimerization between the meso and enantiomeric forms by dynamic gas chromatography. Temperature-dependent measurements were performed, and reaction rate constants were determined using the unified equation of chromatography implemented in the software DCXplorer. The activation barriers of the epimerization were found to be ΔG(≠) = 100.7 kJ mol(-1) at 25°C and ΔG(≠) = 104.5 kJ mol(-1) at 37°C, respectively. The activation enthalpy and entropy were determined to be ΔH(≠) = 70.3 ± 0.4 kJ mol(-1) and ΔS(≠) = -102 ± 2 J mol(-1) K(-1) .
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Affiliation(s)
- Matthias Kamuf
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
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Buerge IJ, Poiger T, Müller MD, Buser HR. Influence of pH on the stereoselective degradation of the fungicides epoxiconazole and cyproconazole in soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:5443-50. [PMID: 16999123 DOI: 10.1021/es060817d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Many pesticides are chiral and consist of two or more enantiomers/stereoisomers, which may differ in biological activity, toxicity, effects on nontarget organisms, and environmental fate. In the last few years, several racemic compounds have been substituted by enantiomer-enriched or single-isomer compounds ("chiral switch"). In this context, the stereoselective degradation in soils is an important part of a benefit-risk evaluation, but the understanding of the environmental factors affecting the chiral preferences is limited. In this study, the stereoselective degradation of the fungicides epoxiconazole and cyproconazole was investigated in different soils, selected to cover a wide range of soil properties. The fungicides were incubated under laboratory conditions and the degradation and configurational stability of the stereoisomers were followed over time using enantioselective GC-MS with a gamma-cyclodextrin derivative as chiral selector. In alkaline and slightly acidic soils, the degradation of epoxiconazole was clearly enantioselective, whereas in more acidic soils, both enantiomers were degraded at similar rates (overall half-lives 78-184 d). The enantioselectivity, expressed as ES = (k(i) - k(j))/ (k(i) + k(j)), ranged from -0.4 in alkaline soils (faster degradation of enantiomer j) to approximately 0 in acidic soils (non-enantioselective), and showed a reasonably linear correlation with the soil pH. The four stereoisomers of cyproconazole (overall half-lives 5-223 d) were also degraded at different rates in the various soils, but only the stereoselectivities between epimers showed some correlations with pH, whereas enantioselectivities did not. Both fungicides were configurationally stable in soils, i.e., no enantiomerization or epimerization was observed. Correlations between pH and ES have previously been reported for other pesticides (metalaxyl, dichlorprop, mecoprop), but the presence or absence of such correlations is not obviously linked to the pathways of degradation. It can be assumed that different microorganisms and enzymes are involved in the primary degradation of these compounds, but on which level soil pH has an influence on ES remains to be investigated.
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Affiliation(s)
- Ignaz J Buerge
- Plant Protection Chemistry, Swiss Federal Research Station (Agroscope), CH-8820 Wädenswil, Switzerland.
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Merino F, Rubio S, Pérez-Bendito D. Supramolecular systems-based extraction-separation techniques coupled to mass spectrometry. J Sep Sci 2006; 28:1613-27. [PMID: 16224955 DOI: 10.1002/jssc.200500161] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The combination of supramolecular chemistry and MS has not only been fruitful in the field of gas-phase fundamental studies of host-guest complexes and supramolecular assemblies. Mass spectrometric analysis has also benefited from the ability of supramolecular systems to behave as pseudophases in which solutes partition from the bulk solvent phase. Supramolecular systems-based extraction and concentration schemes and separation techniques have been widely used in different fields of analytical chemistry and are ideally suited for coupling with MS. This review describes the present status of the application of supramolecular chemistry in mass spectrometric analysis and includes topics such as the use of coacervative liquid-liquid extraction and hemimicelle/admicelle-based SPE of organic compounds prior to chromatography and electrophoresis. It also discusses the recent advances in enantioselective analysis using CD in electrophoresis- and chromatography-MS. The potential and analytical challenges of these approaches in environmental and bioanalytical chemistry, where one can expect significant developments in the future, are outlined.
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Affiliation(s)
- Francisco Merino
- Department of Analytical Chemistry, Campus de Rabanales, Edificio Anexo Marie Curie, University of Córdoba, Córdoba, Spain
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Dregus M, Schmarr HG, Takahisa E, Engel KH. Enantioselective analysis of methyl-branched alcohols and acids in rhubarb (Rheum rhabarbarum L.) stalks. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2003; 51:7086-7091. [PMID: 14611176 DOI: 10.1021/jf030466b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The enantiomeric compositions of 2-methylbutanol (1), 4-methylhexanol (2), 2-methylbutanoic acid (3), and 4-methylhexanoic acid (4) present in rhubarb (Rheum rhabarbarum L.) stalks were determined. Enantiodifferentiation was achieved via multidimensional gas chromatography using heptakis(2,3,6-tri-O-ethyl)-beta-cyclodextrin as a chiral stationary phase. For all compounds the enantiomeric ratios were in favor of the (R)-enantiomers. The alcohols (1 and 2) exhibited generally high excesses of the (R)-enantiomers, the ratios varying slightly from batch to batch. For the acid (3) a rather narrow range averaging 65% (R):35% (S) was observed. The procedure applied to isolate the volatiles (vacuum headspace technique, simultaneous distillation--extraction, liquid--liquid extraction) had no significant impact on the enantiomeric ratios. The study describes for the first time a plant used as food material in which 2-methyl-branched volatiles are not nearly exclusively present as (S)-enantiomers. This information enlarges the current regulatory knowledge regarding the classification of these important flavor compounds as "natural" on the basis of their enantiomeric ratios.
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Affiliation(s)
- Márta Dregus
- Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München, Am Forum 2, D-85350 Freising-Weihenstephan, Germany
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Bicchi C, Brunelli C, Cravotto G, Rubiolo P, Galli M, Mendicuti F. Cyclodextrin derivatives in enantiomer GC separation of volatiles. Part XXI: Complexation of some terpenoids with 2-O-acetyl-3-O-methyl- and 2-O-methyl-3-O-acetyl-6-O-t-hexyldimethylsilyl-γ-cyclodextrins: Molecular Mechanics and Molecular Dynamics. J Sep Sci 2003. [DOI: 10.1002/jssc.200301560] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bicchi C, Brunelli C, Cravotto G, Rubiolo P, Galli M, Mendicuti F. Cyclodextrin derivatives in GC separation of racemates with different volatilities. Part XIX: Thermodynamic aspects of enantioselective GC separation of some volatiles with γ-cyclodextrins 2,3-substituted with methyl and acetyl groups. J Sep Sci 2003. [DOI: 10.1002/jssc.200301387] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Buerge II, Poiger T, Müller MD, Buser HR. Enantioselective degradation of metalaxyl in soils: chiral preference changes with soil pH. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2003; 37:2668-2674. [PMID: 12854703 DOI: 10.1021/es0202412] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Chiral pesticides are often degraded enantio-/stereoselectively in soils. Degradation is typically studied with one or a small number of soils so that it is not possible to extrapolate the findings on chiral preference to other soils. For this study, the fungicide metalaxyl was chosen as a "chiral probe" to investigate its enantioselective degradation in 20 different soils, selected primarily to cover a wide range of soil properties (e.g., acidic/alkaline, aerobic/ anaerobic) rather than to consider soils of agricultural importance. Racemic metalaxyl was incubated in these soils under laboratory conditions, and the degradation of the enantiomers as well as the enantioselective formation/ degradation of the primary major metabolite, metalaxyl acid, was followed over time, using enantioselective GC-MS after ethylation with diazoethane. In aerobic soils with pH > 5, the fungicidally active R-enantiomer was degraded faster than the S-enantiomer (k(R) > k(S)), leading to residues with a composition [S] > [R]. However, in aerobic soils with pH 4-5, both enantiomers were degraded at similar rates (k(R) approximately k(S)), and in aerobic soils with pH < 4 and in most anaerobic soils, the enantioselectivity was reversed (k(R) < k(S)). These considerable soil-to-soil variations were observed with soils from locations close to each other, in one case even within a single soil profile. Liming and acidification of a "nonenantioselective" soil prior to incubation resulted in enantioselective degradation with k(R)> k(S) and k(R) < k(S), respectively. While the enantioselectivity (expressed as ES = (k(R) - k(S))/(k(R) + k(S))) of metalaxyl degradation in aerobic soils apparently correlated with soil pH, no such correlation was found for metalaxyl acid. Reevaluation of published kinetic data for the herbicides dichlorprop and mecoprop indicated similar correlations between soil pH and ES as for metalaxyl.
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Affiliation(s)
- Ignaz I Buerge
- Plant Protection Chemistry, Swiss Federal Research Station, CH-8820 Wädenswil, Switzerland.
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Bicchi C, Brunelli C, Cravotto G, Rubiolo P, Galli M. Cyclodextrin derivatives in GC separation of racemates of different volatility Part XVIII: 2-methyl-3-acetyl- and 2-acetyl-3-methyl-6-O-t-hexyldimethylsilyl-γ-cyclodextrin derivatives. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20020201)25:3<125::aid-jssc125>3.0.co;2-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Beck T, Liepe JM, Nandzik J, Rohn S, Mosandl A. Comparison of Different Di-tert-butyldimethyl-Silylated Cyclodextrins as Chiral Stationary Phases in Capillary Gas Chromatography. ACTA ACUST UNITED AC 2000. [DOI: 10.1002/1521-4168(20001001)23:10<569::aid-jhrc569>3.0.co;2-p] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bicchi C, D'Amato A, Rubiolo P. Cyclodextrin derivatives as chiral selectors for direct gas chromatographic separation of enantiomers in the essential oil, aroma and flavour fields. J Chromatogr A 1999; 843:99-121. [PMID: 10399852 DOI: 10.1016/s0021-9673(99)00202-2] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This article reviews papers published over the period 1995-1998 dealing with the application of cyclodextrin derivatives (CDs) as chiral selector for direct enantiomer GC separation of volatile optically active components in the essential oil, extract, flavour and aroma fields. For each application, the racemate analysed, the CD employed as chiral selector and the matrix investigated are reported. The applications are grouped by analytical technique employed: capillary gas chromatography and capillary gas chromatography-mass spectrometry (GC and GC-MS); two-dimensional gas chromatography (GC x GC); capillary gas chromatography-isotope ratio-mass spectrometry (GC-IRMS); liquid chromatography-capillary gas chromatography (LC-GC).
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Bicchi C, Cravotto G, D'amato A, Rubiolo P, Galli A, Galli M. Cyclodextrin derivatives in gas chromatographic separation of racemates with different volatility. Part XV: 6-O-t-butyldimethylsilyl- versus 6-O-t-hexyldimethylsilyl-? and -? derivatives. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1520-667x(1999)11:7<487::aid-mcs1>3.0.co;2-b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Miranda E, Sánchez F, Sanz J, Jiménez MI, Martínez-Castro I. 2,3-Di-O-pentyl-6-O-tert-butyldimethylsilyl-β-cyclodextrin as a Chiral Stationary Phase in Capillary Gas Chromatography. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1521-4168(19980401)21:4<225::aid-jhrc225>3.0.co;2-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Guillaume YC, Guinchard C. New Statistical Approach to a Gas Chromatography Retention Model: Application to Dichlorophenol Isomers. J Phys Chem B 1997. [DOI: 10.1021/jp971037h] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yves Claude Guillaume
- Laboratoire de Chimie Analytique, Faculté de Médecine et Pharmacie, Place St. Jacques, 25030 Besancon, Cedex, France
| | - Christiane Guinchard
- Laboratoire de Chimie Analytique, Faculté de Médecine et Pharmacie, Place St. Jacques, 25030 Besancon, Cedex, France
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Bartschat D, Wüst M, Mosandl A, Hanssum H. Stereoisomeric flavor compounds LXXVII: 3-Butylhexahydrophthalides: Simultaneous enantioselective analysis, structure elucidation, and sensorial properties of the stereoisomers. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jhrc.1240200502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Bicchi C, D'Amato A, Manzin V, Galli A, Galli M. Cyclodextrin derivatives in the gas chromatographic separation of racemic mixtures of volatile compounds X. 2,3-Di-O-ethyl-6-O-tert.-butyldimethylsilyl-β- and −γ-cyclodextrins. J Chromatogr A 1996. [DOI: 10.1016/0021-9673(96)00254-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Stereoisomeric flavour compounds LXXIV: 2-phenylpropanol, 2-phenylpropanal and 2-phenylpropanal dimethyl acetal: structure elucidation and structure-function relationship. Eur Food Res Technol 1996. [DOI: 10.1007/bf01206094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Affiliation(s)
- Gary A. Eiceman
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003
| | - Herbert H. Hill
- Department of Chemistry, Washington State University, Pullman, Washington 99164
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Shitangkoon A, Vigh G. Systematic modification of the separation selectivity of cyclodextrin-based gas chromatographic stationary phases by varying the size of the 6-O-substituents. J Chromatogr A 1996. [DOI: 10.1016/0021-9673(96)00069-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Icheln D, Gehrcke B, Piprek Y, Mischnick P, König WA, Dessoy MA, Morel AF. Migration of secondary tert-butyldimethylsilyl groups in cyclomalto-heptaose and -octaose derivatives. Carbohydr Res 1996; 280:237-50. [PMID: 8593638 DOI: 10.1016/0008-6215(95)00322-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
When 2,6-di-O-tert-butyldimethylsilylated cyclomalto-oligosaccharides (cyclodextrins) are treated with allyl or methyl iodide and NaH in dry tetrahydrofuran, O-2-->O-3 migration of the secondary 2-O-tert-butyldimethylsilyl groups occurs, leading to 2-O-alk(en)yl-3,6-di-O-tert-butyldimethylsilyl-cyclodextrin derivatives. The detection and identification of the reaction step during which migration occurred is described and possible mechanisms of migration are discussed.
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Affiliation(s)
- D Icheln
- Institut für Organische Chemie, Universität Hamburg, Germany
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Karl V, Kaunzinger A, Gutser J, Steuer P, Angles-Angel J, Mosandl A. Stereoisomeric flavour compounds LXVII. 2-, 3-, and 4-Alkyl-branched acids, part 1: General approach to the synthesis of the enantiopure acids. Chirality 1994. [DOI: 10.1002/chir.530060510] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Karl V, Gutser J, Dietrich A, Maas B, Mosandl A. Stereoisomeric flavour compounds LXVIII. 2-, 3-, and 4-Alkyl-branched acids, part 2: Chirospecific analysis and sensory evaluation. Chirality 1994. [DOI: 10.1002/chir.530060511] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Dietrich A, Maas B, Mosandl A. Diluted modified cyclodextrins as chiral capillary gas chromatographic stationary phases: Influence of the polysiloxane solvents on enantioselectivity and column efficiency. ACTA ACUST UNITED AC 1994. [DOI: 10.1002/mcs.1220060108] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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