GC in the Analysis of Aroma Compounds for the Use in ...

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GC in the Analysis of Aroma Compounds for the Use in
Pharmaceutical, Food and Cosmetic Applications
Leopold Jirovetz
Institute of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14,
A-1090 Vienna, Austria
leopold.jirovetz@univie.ac.at
Aroma compounds have been of high importance for folk medicine, classical medicine, food,
perfumery and cosmetics since ancient times. The renaissance of the use of natural products
in the last years also led to an increasing interest in odour components. Especially because of
their high biological activity and low toxicity aroma compounds are often used in
pharmaceutical products. Although there is a discussion about their usage between
researchers in the field of traditional and classical medicine, the number of scientific papers
including analytical and biological data on odour components is at present higher than ever.
Additionally, the flavouring and conservation of food stuff by odorous volatiles as well as the
search for pleasant smelling raw materials for perfume and cosmetic products in the nature is
not only supported by the food, but also by the perfume and cosmetic industry.
Gas chromatography is the state-of-art method to analyse the constituents of aroma systems
(genuine products like plants and plant parts, extracts, essential oils, synthetic and artificial
compositions). The development of new GC column phases (chiral, high-temperature, waterresistant,
etc.), the construction of GC detectors with a higher sensitivity (mass spectrometers,
Fourier transform infra-red, etc.), the improvements of the GC injector ports and new GC
software programmes made GC the most powerful tool in aroma compound analysis.
Furthermore, the methods to trap volatiles were extended by the introduction of solid-phasemicro-extraction
(SPME) and stir-bar-extraction using various fibres. Both brought some
advantages for the quantification of trapped compounds in correlation to headspace sampling,
because the volatiles evaporate directly from the fibre into the GC injector port. Therefore,
this presentation has three parts.
Analysis of aroma compounds in blood samples after inhalation („aromatherapy“) and
motility experiments on mice
Pure fragrance compounds and essential oils possess mild sedative and activating properties
and have been traditionally used in folk medicine for a long time. So the aim of this project
was to screen and quantify a series of fragrance compounds and essential oils on their
sedative and activating properties, which are partly described in literature. Groups of four
mice each were exposed under standardized conditions to different fragrants. The motility of
the animals was ascertained after inhalation and also after caffeine-induced over-agitation to
collect more detailed information on sedating or activating effects of several compounds and

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their aromatherapeutical usage. In addition, serum samples of the mice were analysed by gas
chromatography-flame ionisation detection (GC-FID), gas chromatography-mass
spectrometry (GC-MS; TI and SIM mode) and gas chromatography-Fourier transform
infrared spectroscopy (GC-FTIR, TRC and SWC mode) to identify and quantify potent
compounds effective in increasing or decreasing the motility of mice by inhalation. Fragrance
compound motility data were correlated with data of the single-odour detection thresholds to
compare volatility effects.
Control of quality, adulteration, chemotype and seasonal dependent composition of essential
oils – stereochemical, antimicrobial and toxicological data of aroma compounds
Patchoulol, a tertiary sesquiterpene alcohol, is the main compound of the essential patchouli
(Pogostemon cablin) oil and responsible for the characteristic odour of this oil, used in Indian
folk medicine, fine perfumery and cosmetics. The values of optical rotation of this alcohol
reported in the literature are very different. In order to determine the optical purity and degree
of racemisation, carbamates of racemic and (-) patchoulol as well as the genuine tertiary
alcohols of patchouli oil were synthesized (isocyanate derivatives) and analysed by GC with
chiral phases. Using GC/FID and GC/MS analyses the compositions of dill (Anethum
graveolens) herb oils from Romania and Kazachstane as well as of dill seed oil from
Romania showed a significant difference (qualitatively and quantitatively) in the composition
of its constituents as well as in the aroma impression GC/FID and GC/MS using chiral phase
columns could be enclosed to determine an adulteration of the essential dill oil from
Kazachstane by synthetic, racemic carvone. The essential oil of a new cultivated basil
(Ocimum basilicum) from Bulgaria were investigated to get information about the chemotype
(various chemotypes with significant target compounds are known from basil of different
geographic origin) of this plant sample. Additional objectives of this work were to identify
the correct stereoisomer of the monoterpene alcohol linalool, as a possible key-constituent of
the Bulgarian sample, by means of chiral phase gas chromatography and to verify the use of
the basil oil in medicine, perfumery and foods. The seasonal depending variation of the
essential oils of various plant parts of Bulgarian Douglas fir (Pseudotsuga menziesii) were
analysed by GC/FID, GC/MS and olfactory evaluations. In all samples about 60 compounds
could be identified with monoterpenes (especially sabinene and β-pinene) as main
constituents. The antimicrobial effects against bacteria, fungi and worms of these volatiles
and their olfactory properties are discussed.
The alteration of the composition of 17 samples of various essential oils used in aroma lamps
and their corresponding headspace samples were analysed by GC/FID, GC/FTIR/MS and
GC-sniffing-technique to obtain information on the change of aroma compounds under cold
and hot conditions. The samples investigated were genuine essential oils, corresponding cold
headspace samples, headspace samples of heated tubs and half-full tubs after the heating
experiments. No detectable quantities of volatile pyrolysis products with health-dangerous
effects were found, but there were significant alterations in the composition. The aromarelevant
compounds of the essential oils investigated pass from the aroma lamp tub to the air
without forming new components and the detected volatiles can therefore be inhaled for
aromatherapeutical use. Only a time-depending change from highly volatile to less volatile
essential oil constituents in the heating experiments was registered.
In total, 15 essential oil samples of the species Cinnamomum (Lauraceae) of various origin
were investigated using gas chromatographic-spectroscopic (GC/FID and GC/MS) and
olfactory methods. The objective of these analyses was to the determination of the content of
(E)-cinnamaldehyde (main compound of cinnamon bark oils), eugenol (main compound of
the cinnamon leaf oils), o-methoxycinnamaldehyde and cinnamyl acetate as well as of the
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critical components coumarin and safrole in order to make statements about the quality
(pharmacopea-quality) and the legal (EU aroma-directice 88/388/EEC including the new
regulations of maximum limits in annex II) use of these oils. Four commercially available
essential cinnamon bark oils and three essential cinnamon leaf oils were found to be
unobjectable and can be used as aromas in foodstuffs and beverages as well as in
pharmaceutical preparations.
Headspace sampling (mono- and sesquiterpenes of white and red vine-blossoms) and solidphase-microextraction
(SPME) in the analysis of aroma compounds (sulphide compounds in
garlic plants and aroma target constituents of rose oils)
Using headspace-analysis in combination with gas chromatographic-spectroscopic methods
(GC/FID and GC/FTIR/MS) as well as with the GC-sniffing-technique it was possible to
correlate blossoms of 7 different white and red vine-varieties respectively by means of the
composition of odour compounds in their headspace considering only dominant-dominant
sesquiterpenes and odour-assistant monoterpenes. All investigated vine-blossoms possess a
mignonette-like, pleasant, floral, dusty, dry, interesting green, fresh, intense and sweet odour
and with regard to the vine-species they only differ in the intensity of single odour-notes, but
not in the direction of the total odour. The odour-profiles and the corresponding multivariate
data analysis of these profiles showed a significant agreement with the results, obtained by
correlations of headspace constituents. The possibility of further connectivities with the
corresponding ampelographic aspects of the investigated vine-species is also discussed.
The aroma compounds of garlic (Allium sativum) of various geographic origin, of the
Cameroonian „garlic plant“ (Hua gabonii) and the Cameroonian „garlic tree“
(Scorodophloeus zenkeri) were analysed by SPME-GC/FID, SPME-GC/MS and olfactory
evaluations.
– The typical garlic aroma of the A. sativum headspace samples is the result of well-known
dominating disulfides, like diallyl disulphide, trans-allyl propenyl disulphide, methyl allyl
disulphide, cis-allyl propenyl disulphide and trans-methyl propenyl disulphide as well as
methyl allyl trisulphide. The target compound for the proof of the natural origin of garlic
samples analysed by gas chromatography, namely 3-vinyl-[4H]-1,2-dithiin, was identified in
all headspace samples in various concentrations.
– The typical garlic aroma of the H. gabonii SPME-headspace sample is not only the result of
well-known disulfides of Allium species, but in plants with garlic aroma - of hitherto rather
rarely identified methyl methylthiomethyl disulphide (=2,4,5-trithiahexane) and di-
(thiomethyl methyl)disulphide (2,4,5,7-tetrathiaoctane). The characteristic disulphide
components of common garlic were found only as minor compounds.
– The main compound of the S. zenkeri headspace is β-caryophellene and the most dominant
sulfidic constituent methyl methylthiomethyl disulphide, while the characteristic Allium
aroma components are only found in low concentrations.
The volatiles of essential oils of rose (Rosa damascena) oils from Bulgaria and Morocco
were trapped by SPME and these headspace-extracts analysed by GC/FID, GC/MS and
olfactometry to identify those compounds, responsible for the pleasant odour of these very
high prized samples used especially in fine-perfumery. Beside odour-active compounds like
rose-oxides and monoterpenes (e.g. geraniol, nerol and citronellol) also aliphatic
hydrocarbons play an important role for the characteristic and long-lasting aroma of essential
rose oils.
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