Comparative analytical studies of fatty acids of the algaChlorella pyrenoidosa

Gas-liquid chromatography, several versions of paper chromatography, and alkaline isomerization have been applied to one preparation ofChlorella fatty acid methyl esters. GLC outranks other methods in rapidity, reproducibility, and resolving power. The presence of nonvolatile components in the sample can lead to erroneous results. Among PC methods which might arise from autoxidation and polymerization are detected. Esters or acids with 14 or fewer C atoms should be analyzed as nonvolatile derivatives. AI, as used here, introduces a systematic error in the determination of linoleic and linolenic acids. The quantitative results of the methods are in agreement for the major components, which all belong to the C₁₀ and C₁₈ series. A number of minor components have been revealed by GLC and/or PC. They are tentatively identified as 12, C₁₂, four C₁₄, C₁₅, two C₁₇, C₁₉, three C₂₀, two C₂₂, and C₂₄ acids. Several of these compounds have been found independently by different methods in hydrogenated form or as radioactive esters. This enhances the certainty of their identification. Eurichment by fractional distillation was essential for their detection. Possible losses in their distillation and other considerations make uncertain the assay of most of the minor components by GLC or PC. Work supported in part by grant RG-4226 from the Division of General Medical Sciences of the U. S. Public Health Service and in part by the Hormel Foundation.