Analysis of Free Fatty acids (SH-200)

Importance of the topic

Free fatty acids (FFAs) are critical markers in food quality control, environmental monitoring and metabolic studies, as they influence flavor, stability and nutritional value of products.

Objectives and study overview

This application note describes a rapid and reliable gas chromatographic method for separating and quantifying nine short-chain free fatty acids (C2–C7) using a SH-200 capillary column and flame ionization detection.

Methodology

An isothermal GC-FID approach was developed to achieve baseline separation of volatile organic acids.
Key method parameters:

• Column temperature: 90 °C
• Injection volume: 0.8 µL (split mode)
• Split flow rate: 40 mL/min
• Carrier gas: Hydrogen at 40 cm/s linear velocity (1.4 mL/min)
• Detector temperature: 250 °C

Instrumentation

• Gas chromatograph: Shimadzu GC with flame ionization detector (FID)
• Analytical column: SH-200 (30 m × 0.25 mm I.D., df = 0.25 µm)

Main results and discussion

The method achieved baseline resolution of acetic, propionic, isobutyric, n-butyric, isovaleric, n-valeric, isocaproic, caproic and heptanoic acids within a single isothermal run. Retention times were consistent and peak shapes demonstrated reproducible quantitation.

Benefits and practical applications

• Rapid, high-throughput analysis for food and beverage quality assurance
• Sensitive monitoring of volatile fatty acids in fermentation and environmental samples
• Minimal sample preparation required, enabling streamlined workflows

Future trends and applications

Integration of mass spectrometric detection or multidimensional GC could improve sensitivity and compound identification. Advances in automated sample handling and online derivatization may further enhance throughput in industrial and research laboratories.

Conclusion

This straightforward isothermal GC-FID method using an SH-200 column provides a fast, reproducible solution for the analysis of short-chain free fatty acids, supporting diverse applications in analytical chemistry and food science.