Geranium Oil on Rxi-5Sil MS (10 m, 0.15 mm ID, 0.15 μm)

Importance of the Topic

Accurate profiling of geranium oil constituents is essential for quality control in fragrance, cosmetics and food industries. Detailed chemical characterization supports authentication, batch consistency and guides formulation of aroma products.

Objectives and Overview of the Study

This work aimed to develop a rapid and reproducible gas chromatographic–mass spectrometric method for separation and identification of volatile components in geranium oil. Using a short, high-efficiency Rxi-5Sil MS capillary column, the study sought to achieve baseline resolution of key monoterpenes, sesquiterpenes and their oxygenated derivatives.

Instrumentation

• Gas Chromatograph: Agilent 7890A with Rxi-5Sil MS, 10 m × 0.15 mm ID, 0.15 µm film.
• Injection: 1 µL split 100:1, injector at 250 °C with wool-packed liner.
• Oven Program: 100 °C to 300 °C at 45 °C/min, then to 320 °C at 30 °C/min, hold 5 min.
• Carrier Gas: Helium at 1.01 mL/min (constant flow).
• Mass Spectrometer: Agilent 5975C quadrupole MS in scan mode (35–500 amu at 11 scans/s), source 230 °C, quad 150 °C, transfer line 300 °C.
• Identification: NIST MS EI library (2005).

Main Results and Discussion

The method resolved 28 peaks between retention times of 0.73 and 2.18 min. Major constituents included linalool (tR 0.732 min), citronellol (1.010 min), geraniol (1.065 min) and geranyl acetate (1.357 min). Sesquiterpenes such as caryophyllene (1.516 min) and germacrene D (1.670 min) were clearly separated. The fast temperature ramping coupled with narrow bore column provided sharp peaks and high throughput.

Benefits and Practical Applications

• Rapid profiling supports routine quality control and purity assessment.
• High resolution facilitates detection of adulteration or batch variation.
• Applicable to industry settings requiring fast turnaround.

Future Trends and Possibilities

Advancements may include two-dimensional GC for enhanced separation, use of alternative carrier gases or columns to reduce analysis time, and coupling with chemometric tools or machine learning for untargeted fingerprinting and predictive quality models.

Conclusion

The described GC-MS method on an Rxi-5Sil MS column provides a robust, fast and high-resolution approach to characterize geranium oil volatiles. It balances analysis speed with comprehensive compound identification, making it suitable for both research and industrial applications.

References

1. Restek Corporation. Application note: Geranium Oil on Rxi-5Sil MS, 2019.
2. NIST Mass Spectral Library (2005).