Fatty Acid Analysis of Edible Oils by GC —Comparing Helium and Hydrogen as Carrier Gases— —Comparing Analysis by GC with a Simple Screening Analysis by LC-MS—

Significance of the Topic

Edible oils are predominantly composed of triacylglycerols, whose fatty acid profiles critically influence food functionality, nutrition, and quality control. Precise determination of fatty acid composition supports product authentication, safety assessment, and compliance in food and industrial applications.

Objectives and Study Overview

This study employs the compact Brevis GC-2050 gas chromatograph with FID to quantify fatty acid methyl esters (FAMEs) in sixteen edible oils. It compares helium and hydrogen as carrier gases for GC-FID performance and contrasts detailed GC-FID data with rapid LC-MS screening results.

Methodology and Instrumentation

The workflow converts oil samples into FAMEs via BF₃-methanol derivatization, followed by chromatographic separation and detection. Analyses were conducted under optimized conditions for both carrier gases and complemented by high-throughput flow-injection LC-MS screening.

• Sample Derivatization: Oils (~85–100 mg) spiked with triundecanoin internal standard were treated with 7% BF₃-methanol at 100 °C for 45 min, then extracted into hexane and dried over sodium sulfate.
• GC-FID Analysis: Shimadzu Brevis GC-2050 with AOC-30i, SH-2560 column (100 m×0.25 mm, 0.20 µm). Helium at 1.0 mL/min or hydrogen at 25 cm/s, split injection (1 µL, ratio 200:1), injector/detector at 250 °C, column temperature programs tailored for each gas.
• LC-MS Screening: Nexera LCMS-2050 single quadrupole with flow-injection analysis of 100× diluted oils in 2-propanol containing DHA internal standard, achieving one minute per sample.

Key Results and Discussion

Calibration with a 37-component FAME standard yielded excellent resolution under both helium and hydrogen, with hydrogen reducing run times by about 25% and saving 79% of carrier gas. Analysis of real oil samples produced overlapping chromatograms for linseed oil under both gases. Quantitative comparisons across sixteen oil types showed fatty acid percentages within 0.2% between helium and hydrogen methods, confirming methodological consistency. GC-FID results correlated closely with LC-MS screening data, demonstrating the latter’s capability for rapid, high-throughput profiling despite minor composition differences.

Benefits and Practical Applications

• Hydrogen as a carrier gas offers substantial gas savings and faster analysis without compromising resolution, addressing helium availability concerns.
• The Brevis GC-2050’s compact footprint and carrier gas saving mode reduce laboratory space and operational costs.
• Flow-injection LC-MS provides one-minute screening per sample, ideal for quality control and urgent safety assessments.

Future Trends and Potential Applications

Anticipated developments include wider adoption of hydrogen GC methods as a sustainable alternative, integration of GC and LC-MS platforms for comprehensive lipid profiling, and enhanced automation and data analytics for real-time monitoring in food and industrial laboratories.

Conclusion

The Brevis GC-2050 effectively determined fatty acid compositions in edible oils using both helium and hydrogen carriers, with hydrogen proving a viable, resource-efficient alternative. Complementary FIA-MS screening on a single quadrupole LC-MS enabled rapid high-throughput analysis. Together, these approaches offer flexible, accurate solutions for routine quality control and research in lipid analysis.

References

1. Shimadzu Application News: Simple Method for Screening Analysis of Vegetable Oils Using a Single Quadrupole Mass Spectrometer, 01-00674-EN.
2. AOAC Official Method 996.06: Fat (Total, Saturated, and Unsaturated) in Foods: Hydrolytic Extraction Gas Chromatographic Method.