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To profile the fatty acids (Fas) composition of suet oil (SO), a precolumn methylesterification (PME) combined with gas chromatography quadrupole mass spectrometry (GC-EI-qMS) was reported in this study.The optimal condition of PME,including methyl reagent volume (10 mL), temperature (60 C) and time (10 min) were investigated by Box-Behnken design (BBD).Spectral library(NIST 08) and/or standard compounds were used to identify up to 25 Fas in SO, representing 90.89% of the total peak areas.And then, 10 main Fas derivatized into fatty acid methyl esters (FAMEs) were quantified by GC-EI-qMS.The correlation coefficient of 10 FAMEs were all at 0.999 while the lowest quantified level was 0.01 μg/mL.The recoveries of 10 FAMEs were 82.1%-98.7%with relative standard deviations of 2.2%-6.8%.The method detection limits (LOQ) were 1.25-5.95 μg/L.The Fas composition distributed widely from 12 to 20 carbon, in which hexadecanoic acid and octadecanoic acid were the main ingredients in SO.And then,Eighteen SO samples purchased from Qinhai, Anhui and Jiangsu were successfully classified into three groups by principal component analysis (PCA) according to the contents of ten detected Fas.The results showed that all SO samples were rich in Fas but with significant difference corresponding to different origins.The proposed method could be useful in quality control and could probably be used for SO differentiation based on the Fas metabolomic profile.