抄録
Seven Japanese laboratories provided with high resolution nuclear magnetic resonance (NMR) equipment undertook a collaborative study for determining docosahexaenoic acid (DHA) and n-3 fatty acids in fish oils with NMR. This study was organized by the DHA/NMR subcommittee of the Japan Oil Chemists’ Society and conducted as a part of an IUPAC collaborative study (Project 3/98 of the commission VI-6 on Oils, Fats, and Derivatives). At each laboratory, examination was made of six blind duplicate fish oils, as follows; refined tuna oil, two extracted tuna oils, extracted bonito oil, extracted salmon oil and extracted sardine oil 9 to 30 mol% DHA and 20 to 35 mol% n-3 fatty acids. To ensure maximum accuracy of determination, signal area measurement and addition of the internal standard solution were taken as critical control points. Repeatability coefficient of variation (CVr) ranged from 0.8 to 2.6% and reproducibility coefficient of variation (CVR) ranged from 1.4 to 3.3% for DHA weight concentration (mg/g); CVr from 0.4 to 2.2% and CVR from 0.7 to 3.1% for DHA (mol%); CVr from 0.2 to 1.1% and CVR from 1.1 to 2.2% for total n-3 fatty acids (mol%). The present method was thus shown to qualify for use as a tentative official method of the Japan Oil Chemists’ Society.
