Geranium Oil on Rxi-5Sil MS (20 m, 0.18 mm ID, 0.18 μm)

Importance of the Topic

Geranium essential oil is valued in perfumery, cosmetics and aromatherapy for its complex aromatic profile and potential biological activities. Reliable compositional analysis is critical for quality control, authentication and formulation consistency. Gas chromatography coupled with mass spectrometry (GC–MS) remains a gold standard to separate, identify and quantify volatile terpenoids and other minor constituents in essential oils.

Objectives and Overview of the Study

This application note aimed to demonstrate the performance of the Rxi-5Sil MS column (20 m × 0.18 mm ID, 0.18 µm film thickness) for rapid, high-resolution profiling of geranium oil. Key goals included efficient separation of isomeric compounds, accurate identification via NIST spectra matching and reproducible retention times under a fast temperature program.

Methodology and Instrumentation

The essential oil was diluted in acetone at 5 % (v/v) and 1 µL was injected in split mode (100:1) using a Topaz inlet liner with wool. The GC oven was programmed from 100 °C (0.25 min hold) to 320 °C at 17.5 °C/min (10 min hold). Helium was employed as carrier gas at 1.01 mL/min constant flow. A quadrupole mass spectrometer scanned from m/z 35–500 at 5 scans/s. Transfer line, ion source and quadrupole temperatures were 300 °C, 230 °C and 150 °C, respectively. All peaks were identified by comparison to the NIST 2005 MS EI library.

Main Results and Discussion

The total run time was under 7 minutes, achieving baseline separation of 28 terpenoid and aromatic esters. Major compounds included:

• Linalool (tR ≈ 1.85 min)
• Citronellol (tR ≈ 2.60 min)
• Geraniol (tR ≈ 2.75 min)
• Geranyl acetate (tR ≈ 3.54 min)
• Neryl acetate (tR ≈ 4.17 min)

Adequate resolution of isomer pairs such as rose oxide isomers, menthone/isomenthone and citronellyl esters was demonstrated. Peak identities and relative abundances were consistent with typical Pelargonium graveolens profiles.

Benefits and Practical Applications

• High-throughput screening in QA/QC laboratories.
• Authentication of natural versus adulterated geranium oil.
• Support for fragrance formulation by quantifying key aroma contributors.
• Rapid method compatible with routine industrial workflows.

Future Trends and Applications

Advances in two-dimensional GC–MS and high-resolution accurate-mass spectrometry will further enhance the detection of trace components and stereoisomers in essential oils. Integration with chemometric analysis can enable classification of geographical origin and botanical species. Online coupling with preparative fractionation may facilitate isolation of bioactive constituents for pharmaceutical and cosmetic research.

Conclusion

The Rxi-5Sil MS column provides fast, reproducible separation of geranium oil volatiles, enabling comprehensive compositional analysis in less than 7 minutes. Its performance supports quality control and product development in industries relying on essential oil authenticity and consistency.

References

• Restek Corporation. Application note: Geranium Oil on Rxi-5Sil MS (20 m, 0.18 mm ID, 0.18 µm). 2019.