Analysis of Fatty Acid Composition by Gas Chromatography Using Hydrogen or Nitrogen as an Alternative Carrier Gas to Helium: a JOCS Collaborative Study

A collaborative study among 11 different Japanese laboratories was undertaken to devise an analytical method for determining the fatty acid composition of fats and oils by gas chromatography (GC) using hydrogen (H₂) or nitrogen (N₂) as carrier gases alternative to helium (He). This collaborative study was organized by the Alternative Gas for the GC Subcommittee of the Japan Oil Chemists' Society and was evaluated by analyzing a standard mixture of fatty acid methyl esters (Supelco 37 Component FAME Mix), soybean, and sardine oils. On a 50% cyanopropyl siloxane capillary column, the resolution of 37 FAME mixtures using He, H₂, or N₂ gas was greater than 1.0. For the area% of the 37 FAME mixtures, the reproducibility relative standard deviations ranged from 0.59 to 4.72% for He gas, 0.39 to 4.96% for H₂ gas, and 0.60 to 4.91% for N₂ gas. No significant difference was observed in the area% for the 37 FAME mixtures among the three carrier gases. Furthermore, no significant differences in the percentages of major fatty acids in the soybean and sardine oils were detected between the different carrier gases. This study also determined that the analysis time was prolonged when N₂ gas was used compared to when H₂ or He gas was used. However, a cyanopropyl siloxane capillary column for fast and selective separation could improve the analysis time using N₂ gas. Therefore, we conclude that the present method using H₂ or N₂ gas qualifies as a tentative official method of the Japan Oil Chemists' Society.