Essential oils enantioselective analysis

Konig WA, Krebber R, Evers P, Bruhn G, Stereochemical analysis of constituents of essential oils and flavor compounds by enantioselective capillary gas chromatography HRC 13 328—332, 1990. 

Shellie R, Marriott P, Cornwell C, Application of comprehensive two-dimensional gas chromatography (GC GC) to the enantioselective analysis of essential oils, J Sep Sci 24 823-830, 2001. 

Maas B, Dietrich A, Mosandl A, Enantioselective capillary gas chromatography — Olfactometry in essential oil analysis, Naturwissenschafien 80 470 72,1993. 

Shellie R, Mondello L, Dugo G, Marriott P, Enantioselective gas chromatographic analysis of monoterpenes in essential oils of the family Myrtaceae, Flavour Fragr J 19 582-585, 2004. 

Kreck, M., Scharrer, A., Bilke, S., Mosandl, A. (2002) Enantioselective analysis of monoter-pene compounds in essential oils by stir bar sorptive extraction (SBSE)-enantio-MDGC-MS. Flavour Fragrance ]. 17 32-40. 

Fig. 17.5 Enantioselective analysis of germacrene D from the essential oil of different Solidago canadensis plants, using the enantio-MDGC-mass spectrometry (MS) technique [21]...

Maas, B., A. Dietrich, and A. Mosandl, Enantioselective Capillary Gas Chromatography— Olfactometry in Essential Oil Analysis. Naturwissenschaften, 1993 80, 470-472. 

C. Askari, P. Kreis, A. Mosandl and H.-G. Schmarr. Chiral Compounds of Essential Oils Vll Quality Evaluation of Mentha Oils, using enantioselective CGC-Analysis of Monoterpenoid Constituents. Arch. Pharm., 325, 35-39 (1992). 

The GCxGC resolution advantage is known to improve the efficiency of enantioselective essential oil analysis (in contrast to one-dimensional analysis). In a single temperature-programmed analysis, the individual antipodes of optically active components can be separated and are effectively free from matrix interferences. The enantiomeric compositions of a number of monoterpene hydrocarbons and oxygenated monoterpenes in Australian tea tree Melaleuca alternifolia), including sabinene, a-pinene, (3-phellandrene, limonene, trans-sabinene hydrate, ds-sabinene hydrate, linalool, terpinen-4-ol, and a-terpineol shown in Figure 7,... 

Prerequisites for the use of GC, such as volatility and thermal stability of the analytes, restrict exclusive application of this technique. Thus, this very power-fill technique for enantioselective analysis of many natural compounds (essential oils, terpenoids, food components, etc.) may fail for most pharmaceutical and biomedical applications, where the samples are polar and nonvolatile or too thermolabUe. 

After successful application of enantioselective GC to the analysis of enantiomeric composition of monoterpenoids in many essential oUs (e.g., Werkhoff et al., 1993 Bicchi et al., 1995 and references cited therein), the studies have been extended to the sesquiterpene fraction. Standard mixtures of known enantiomeric composition were prepared by isolation of individual enantiomers from numerous essential oils by preparative GC and by preparative enantioselective GC. A gas chromatographic separation of a series of isolated or prepared sesquiterpene hydrocarbon enantiomers, showing the separation of 12 commonly occurring sesquiterpene hydrocarbons on a 2,6-methyl-3 pentyl-p-cyclodextrin capillary column has been presented by Kbnig et al. (1995). Further investigations on sesquiterpenes have been published by Kbnig et al. (1994). However, due to the complexity... 

A further approach, the detection frequency method [74,75], uses the number of evaluators detecting an odor-active compound in the GC ef uent as a measure of its intensity. This GC-0 method is performed with a panel composed of numerous and untrained evaluators 8-10 assessors are a good agreement between low variation of the results and analysis time. It must be added that the results attained are not based on real intensities and are limited by the scale of measurement. An application of the detection frequency method was reported for the evaluation of leaf- and wood-derived essential oils of Brazilian rosewood (A. rosaeodora Ducke) essential oils by means of enantioselective-GC-0 (Es-GC-0) analyses [76]. 

Chiral compounds are frequently foimd among the flavor volatiles of fruits and, like many naturally occurring chiral compounds, one enantiomer usually exists with a greater preponderance when compared with its antipode. Chiral odor compounds may show qualitative and quantitative differences in their odor properties (7). For example, (/ )-(+)-limonene has an orange-like aroma while (5)-(-)-limonene is turpentine-like (5)-(+)-carvone is characteristic of caraway while its enantiomer has a spearmint odor (2). However, other chiral compounds, such as y 6-lactones, show very little enantioselectivity of odor perception (7). The occurrence of chiral flavor compounds in enantiomeric excess provides the analyst with a means of authenticating natural flavorings, essential oils, and other plant extracts. The advent of cyclodextrin-based gas chromatography stationary phases has resulted in considerable activity in the analysis of chiral compounds in flavor extracts of fruits, spices and other plants (i-7). 

Authenticity assessment of genuine substances of coriander oil (Coriander sativum L.) has been the object of a work dealing with the analysis of 10 authentic coriander essential oil samples of different origins [29]. The techniques used were GC-IRMS and enantioselective two-dimensional GC using a chiral cyclodextrin derivative as the stationary phase. The enantiomer ratio and the 8 C values of 12 characteristic components were compared with those of commercially available... 

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