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

Importance of the Topic

Citronella essential oil is widely used in fragrances, flavorings and insect repellents. Accurate chemical profiling ensures product quality, authenticity and regulatory compliance across cosmetic, food and pharmaceutical industries.

Objectives and Study Overview

This application note demonstrates a rapid gas chromatography–mass spectrometry method for the separation and identification of 28 key components in citronella oil using an Rxi-5Sil MS capillary column.

Methodology and Instrumentation

The analysis was performed under the following conditions:

• Column: Rxi-5Sil MS, 20 m × 0.18 mm ID, 0.18 μm film thickness
• Sample: Citronella oil diluted to 5% in acetone
• Injection: 1 µL split (100:1), inlet temperature 250 °C using a 4.0 mm ID wool-packed liner
• Oven program: 100 °C hold 0.25 min, ramp at 17.5 °C/min to 320 °C, hold 10 min
• Carrier gas: Helium constant flow at 1.01 mL/min
• Detector: Agilent 5975C quadrupole MS in scan mode (35–500 amu, 5 scans/sec)
• Transfer line: 300 °C; Source: 230 °C; Quadrupole: 150 °C

Peaks were identified by matching spectra to the NIST MS EI library (2005).

Main Results and Discussion

The method achieved baseline separation of 28 constituents within a 7-minute window. Major monoterpenes such as α-pinene (tR 1.25 min), D-limonene (1.57 min), linalool (1.85 min) and citronellal (2.16 min) were resolved alongside sesquiterpenes including germacrene D (4.35 min), α-muurolene (4.44 min) and cadinene isomers (4.58–4.70 min). Minor oxygenated compounds like geraniol, eugenol and eudesmol isomers were also clearly detected.

Benefits and Practical Applications

The fast analysis time and high resolution make this method ideal for routine quality control of citronella oil batches. It supports authentication, detects adulteration and guides formulation in fragrance, personal care and repellent products.

Future Trends and Potential Applications

Advances such as two-dimensional GC, high-resolution MS and automated data processing will further enhance volatile fingerprinting. Integration with chemometric models can improve adulteration detection and classification of essential oil chemotypes.

Conclusion

This GC-MS method on an Rxi-5Sil MS column provides a robust, rapid and reproducible profile of citronella oil components, supporting industry requirements for quality and authenticity verification.

Reference

• NIST MS EI spectra library, 2005