Chemical analysis of polymerization products in abused fats and oils

For more than a decade, numerous analytical methods have been proposed for the detection and measurement of polymers in vegetable fats and oils. Many of the methods have been little more than laboratory curiosities, either because they were concerned with only very specific compounds or were too cumbersome and time consuming to become very popular. More recently, a number of methods in common use for analysis of fats and oils has been shown to be useful for indirectly measuring polymeric materials in heat abused oils. The present report shows, by the use of gel filtration chromatography, the validity of two of the indirect methods of estimating polymeric products of abused fats and oils. These methods are: the estimation of polymers through changes in the iodine value and the measurement of retention materials on a gas liquid chromatographic column. A new simplified internal standard gas liquid chromatographic procedure utilizing triglyceride standards also is presented. This latter method permits estimating the degree of degradation of vegetable fats and oils by any laboratory capable of determining the fatty acid composition of a sample by gas liquid chromatography.