Angela Shannon

Analysis of fatty acid mixtures : comparison of two " absolute " methods of determination.

Abstract We have applied a method using an internal standard to the determination of absolute quantities of fatty acids; these quantities are more fundamental than the relative or percentage values usually obtainable by gas-liquid chromatography. The use of weight units allows direct comparison of different samples, and removes the dependence of individual values on the values of all the other components produced by the use of percentages. Use of the internal standard gives data comparable with those of older methods, but is applicable to much smaller samples. In addition to its speed and convenience it corrects automatically for small errors in manipulation during preparation of the samples for analysis; in particular, this method automatically corrects for the unknown losses which occur during injection of a sample into the gas-liquid chromatography apparatus. The internal standard method is particularly useful for samples which are too small for independent measurement of the weight of total fatty acid.