South African fish products. Part XXII. Periodic acid as a reagent in the analysis of the unsaponifiable fractions of natural fats

Abstract

A study of the distribution, nature and metabolism of glyceryl ethers in natural fats is in progress, and as a preliminary to the publication of results, a method which has been used for the quantitative estimation of α‐glyceryl others in the unsaponifiable fractions of natural fats is described. In this method the unsaponifiable matter of the fat is treated in solution in ethyl alcohol or ethyl acetate with an excess of periodic acid solution, and the formaldehyde generated is estimated gravimetrically. The results obtained have been checked by volumetric estimation of the periodic acid consumed in the reaction. In very many cases, as with batyl alcohol itself, agreement has been observed between the results of the two methods. Diserepancies with a number of fats indicate, however, the existence in their unsaponifiable matters of substances other than α‐glyceryl others which are attacked by periodie acid. These cases are under fuller investigation.

Studies of sebum. 7. The composition of the sebum of some common rodents

“…The corresponding fractions from the guinea pig, rabbit and rat, when analysed by the periodate method of Karnovsky & Rapson (1946), were found to contain 66-4, 38-2 and 33-4 % respectively of diols (calculated as the C20 diol). Each fraction on oxidation with lead tetra-acetate yielded formaldehyde (dimedone complex), together with long-chain fatty acids, indicating that all contained alkane-1:2-diols.…”

Studies of sebum. 9. Further studies of the composition of the unsaponifiable matter of human-forearm ‘sebum’

“…'Alkane 1:2-diolW'. Fraotions 5 and 6 (Table 1) were subjected to periodate oxidation (Karnovsky & Rapson, 1946 Table 2. Quantitative analy8i of the uaz alohol8 and comtponent fatty acids of human-forearn sebum Results are expressed as percentage of total material recovered from the gas chromatogram.…”