It has been suggested that serum concentrations of polyunsaturated essential fatty acids correlate with the symptoms or severity of various diseases, including depression and Alzheimer-type dementia, and that determination of serum fatty acids might be important for disease diagnosis. Thus, we developed to analyze serum fatty acids in healthy individuals by using a high-performance liquid chromatography method with fluorescence detection, because free fatty acids have a carboxyl group that can be derivatized with a fluorescent reagent, 4-N,N-dimethylaminosulfonyl-7-N-(2-aminoethyl)amino-2,1,3-benzoxadiazole. This approach could quantify five types of free fatty acids [α-linolenic acid (ALA), palmitoleic acid (PLA), arachidonic acid (AA), linoleic acid (LA) and oleic acid (OA)] in human serum. The detection limits of the method were in the range of 2.29-4.75 fmol (signal-to-noise ratio 3), and absolute concentrations of ALA, PLA, AA, LA and OA were 8.27 ± 1.04, 18.8 ± 2.95, 49.9 ± 4.03, 230 ± 18.1 and 201 ± 22.1 µM, respectively.
