Linoleic acid-C ethyl ester is intended for use as an internal standard for the quantification of linoleic acid ethyl ester by GC- or LC-MS. Linoleic acid ethyl ester is an esterified form of linoleic acid. Linoleic acid is an essential fatty acid and one of the most abundant polyunsaturated fatty acids in the Western diet. Deficiencies in linoleic acid are linked to defective wound healing, growth retardation, and dermatitis. Linoleic acid is metabolized in both plants and animals to form 9(S)- and 13(S)-HODE.