The selective order in which methyl esters of fatty acids form urea complexes was correlated with the fatty acid structure. Detailed information about the preferential order in which inclusion compounds are formed was obtained by fractionating complex oils (e.g., butter, lanolin, cod liver). The preferential order was correlated with GLC retention times, and the detection of trace amounts of fatty acids (<0.1%) was possible. Urea adductability values (UAV) are proposed as a useful means of expressing preferential order of the formation of inclusion compounds

The official AOAC method, 15.164, for determining the fat content of cheese was compared in six laboratories with the Schmid - Bondzynski - Ratzloff method, as adopted by the Food and Agriculture Organization of the United Nations. The results of analysis by the two methods are not significantly different; thus, the two methods can be used interchangeably.

This proposed urea fractionation procedure concentrates esters with similar GLC retention times in separate fractions. GLC peaks of esters present in cocoa butter oil in trace amounts (0.001–0.1%), which are normally hidden under major peaks, can then be detected. By modified programmed temperature GLC techniques, it is possible to detect the short and long chain length fatty acids present in cocoa butter oil. The odd and even chain length saturated acids from C10 to C28, mono-unsaturates C16 to C24, branched acids C16 to C24, and linoleic and linolenic acids were detected.

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