Chemical Analysis of Essential Oil Compounds

Chemical analysis of essential oils entails the characterisation of complex mixtures of volatile organic compounds, predominantly terpenes and oxygenated derivatives. Hydrodistillation or steam distillation yields the crude oil, which is then subjected to gas chromatography coupled with mass spectrometry (GC-MS) and flame ionisation detection (GC-FID) for qualitative and quantitative profiling. Enantioselective chromatography allows determination of chiral purity and enantiomeric excess, revealing biosynthetic pathways and potential bioactivity differences. Multivariate statistical approaches, such as principal component analysis, are increasingly applied to compare compositional profiles across species, geographic origins or extraction conditions. Such analyses underpin the exploration of essential oils in pharmacology, aromatherapy, agriculture and food science, and inform quality control and standardisation practices on a global scale.

Research from Nature Portfolio

Recent studies have described the essential oil from the leaves of Steiractinia sodiroi for the first time. Steam distillation yielded a low-percentage oil rich in monoterpene and sesquiterpene hydrocarbons. Two orthogonal GC columns identified sixty-seven compounds accounting for over 90 % of the oil mass. Major constituents included limonene, sabinene, germacrene D, α-pinene, δ-cadinene and (E)-β-caryophyllene. Enantioselective analysis using cyclodextrin-based columns revealed three enantiomerically pure compounds and several with notable enantiomeric excess, while α-pinene occurred as a racemate. Quantification was achieved through relative response factors calculated from combustion enthalpies, demonstrating a rigorous approach to absolute composition measurement.

Chemical Analysis of Essential Oil Compounds publication trend

The graph below shows the total number of articles in chemical analysis of essential oil compounds across all publications each year (not limited to Nature Index journals).

Technical terms

Gas chromatography–mass spectrometry (GC-MS): Technique separating volatile constituents and identifying them via mass spectral fragmentation.

Gas chromatography–flame ionisation detection (GC-FID): Quantitative method measuring ion currents from combusted compounds to determine concentration.

Enantioselective analysis: Chromatographic separation of chiral molecules to establish enantiomeric composition and purity.

Monoterpenes and sesquiterpenes: Hydrocarbon classes comprising 10- and 15-carbon isoprene units, respectively, abundant in essential oils.

Bioautography: Technique combining chromatographic separation with biological assays to localise antimicrobial or antioxidant activity.

References

1. A new essential oil from the native Ecuadorian species Steiractinia sodiroi (Hieron.) S.F. Blake (Asteraceae): chemical and enantioselective analyses. Scientific Reports (2023).
2. Chemical Composition and Biological Activity of Essential Oil from Leaves and Fruits of Limoncillo (Siparuna muricata (Ruiz & Pav.) A. DC.). Antibiotics (2023).
3. Chemical Composition, Antimicrobial and Antioxidant Bioautography Activity of Essential Oil from Leaves of Amazon Plant Clinopodium brownei (Sw.). Molecules (2023).
4. A New Essential Oil from the Leaves of Gynoxys rugulosa Muschl. (Asteraceae) Growing in Southern Ecuador: Chemical and Enantioselective Analyses. Plants (2023).