Simultaneous Determination of Free Fatty Acids and Esterified Fatty Acids in Rice Oil by Gas Chromatography

Author(s):  
Ken'ichi Ichihara ◽  
Chihiro Kohsaka ◽  
Yoshihiro Yamamoto ◽  
Takehiro Masumura
1996 ◽  
Vol 79 (6) ◽  
pp. 1471-1476
Author(s):  
Yukari Tsumura ◽  
Yumiko Nakamura ◽  
Yasuhide Tonogai ◽  
Tadashi Shibata

Abstract A convenient method is described for the determination of tricyclazole in brown rice, and the interference of free fatty acids with flame thermionic detection (FTD) is reported for the first time. Brown rice is extracted with acetone, the extract is filtered, and the filtrate is evaporated. To the residue is added 10% (w/v) NaCI solution, and the mixture is extracted with ethyl acetate. The extract is charged on a Sep-Pak Plus silica cartridge. Free fatty acids are removed from the rice by washing with diethyl ether, and tricyclazole is eluted with acetone-n-hexane (1 + 1). Tricyclazole is determined on a DB-1 capillary column by gas chromatography with FTD (GC–FTD). Linoleic acid and oleic acid, which have essentially the same retention time as tricyclazole, cannot be detected by FTD. Thus, without the Sep- Pak Plus silica cleanup, the peak height of tricyclazole in the chromatogram decreased, the extent depending on the concentration of linoleic acid, n-Hexane–acetonitrile partitioning was not used for cleanup because it could not remove 50% of the free fatty acids. Recoveries (mean ± standard deviation, n = 5) of tricyclazole from rice fortified at 2 and 0.1 ppm were 90.5 ±9.4% and 81.3±10.6%, respectively. The limit of quantitation was 0.05 ppm.


1992 ◽  
Vol 62 (10) ◽  
pp. 580-585 ◽  
Author(s):  
Elżbieta Wojciechowska ◽  
Anna Pielesz ◽  
Andrzej Wlochowicz

We have made an analysis of the lipids deposited on the surface of wool staple fibers divided into tip and base sections prior to investigation. The analysis is limited to a determination of free fatty acids and the ester fraction by gas chromatography and mass spectrography. The findings show that the changes in lipid composition, both quantitative and qualitative, depend on the location from which the lipids have been sampled.


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