Squalene in oils determined as squalene by gas-liquid chromatography after hydrogenation of methyl esters

Abstract

Low levels (≤0.1%) of squalene were anticipated in oils from the blubber of the harp seal Phoca groenlandica. The traditional route of saponification and analytical examination of the total unsaponifiables was unattractive. A method developed for squalene in olive oil, reportedly present in the range of 0.3-0.7%, was based on total conversion of the oil to methyl ester of fatty acids by alkali transesterification, followed by hydrogenation over Adam's catalyst (PtO2). The analysis of the fully saturated methyl esters and any squalane produced concurrently was by gas-liquid chromatography. This method was satisfactory for the small amounts, 0.03% or less, of squalene in seal oil and is also illustrated for olive oil. A flame-ionization detector excessive response of approximately 25% was observed for all levels of squalene tested. The calculated factor of 1.22 should be applied to the peak area for squalane due to the higher response of hydrocarbons relative to the methyl esters of fatty acids and the system of oil components if reporting as fatty acids.