Summary
Existing ultraviolet spectrophotometric methods have been modified for application primarily to the detection and estimation of low proportions of conjugated and nonconjugated unsaturated constituents in fats, oils, and soaps. The method is applicable also to fatty materials having high proportions of these constituents.
Modifications include corrections for absorption by interfering substances, use of alkaline glycerol as an isomerization medium in the analytical procedure, and correction of absorption data on the isomerized product for absorption by conjugated constituents in the material before isomerization.
The presence of small proportions of highly unsaturated conjugated and nonconjugated compounds is established in lards, tallows, tallow soaps, and highly purified esters and acids. Tall oil fatty acids are shown to contain approximately 10% of conjugated diene acids and a small amount of linolenic acid.
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One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, United States Department of Agriculture.
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Brice, B.A., Swain, M.L., Schaeffer, B.B. et al. Spectrophotometric determination of small proportions of polyunsaturated constituents in fatty materials. Oil Soap 22, 219–224 (1945). https://doi.org/10.1007/BF02636707
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DOI: https://doi.org/10.1007/BF02636707