DEFINITION
This method is for the separation and quantitative determination of the triglycerides in liquid vegetable oils, in terms of their molecular weight and degree of unsaturation as a function of their equivalent carbon number (ECN), which is sometimes referred to as the partition number, using high-performance liquid chromatography (Reference 1).

SCOPE
This method is applicable to all vegetable oils containing triglycerides of long-chain fatty acids. The method is especially applicable to the detection of the presence of small quantities of semidrying oils (rich in linoleic acid) in vegetable oils containing oleic acid as the predominant unsaturated fatty acid, such as olive oil, palm oil, and peanut oil. The triglycerides are separated according to their equivalent carbon number by high-performance liquid chromatography (reversed-phase polarity) and quantitated by interpretation of the chromatograms. Three detector options are given: (a) differential refractometer, (b) UV detector, and (c) mass detector.