Authenticated fatty acid methyl ester standards

The gas chromatography procedure has been described in detail previously (McNamara et al., 2009 (link)). Briefly, erythrocyte, PFC, and thalamus total fatty acid composition were determined with a Shimadzu GC-2014 equipped with an auto-injector (Shimadzu Scientific Instruments Inc., Columbia MD). The column was a DB-23 (123–2332): 30 m (length), I.D. 0.32 mm wide bore, film thickness of 0.25 µM (J&W Scientific, Folsom CA). Fatty acid identification was determined using retention times of authenticated fatty acid methyl ester standards (Matreya LLC Inc., Pleasant Gap PA). Analysis of fatty acid methyl esters is based on areas calculated with EZstart 7.4 software. Fatty acid composition is expressed as weight percent of total fatty acids (mg fatty acid/100 mg fatty acids). All samples were processed by a technician blinded to treatment. The primary measure of interest was DHA.

RBC and PFC total fatty acid composition were determined with an Agilent 9820A equipped with an auto-injector (Agilent Technologies, Santa Clara, CA). The column was a DB-23 (123-2332): 30 m (length), I.D. 0.32 mm wide bore, film thickness of 0.25 μM (J&W Scientific, Folsom CA). Fatty acid identification was determined using retention times of authenticated fatty acid methyl ester standards (Matreya LLC Inc., Pleasant Gap PA). Analysis of fatty acid methyl esters is based on areas calculated with OpenLab CDS ChemStation software. Fatty acid composition is expressed as weight percent of total fatty acids (mg fatty acid/100 mg fatty acids). Primary measures of interest were DHA, AA, and the AA/DHA ratio. Samples were processed by a technician blinded to diet assignment.