A. Nishiyamanaruke et al., HPLC DETERMINATION OF UNDERIVATIZED FATTY-ACIDS SAPONIFIED AT 37-DEGREES-C ANALYSIS OF FATTY-ACIDS IN OILS AND TISSUES, Analytical letters, 31(14), 1998, pp. 2565-2576
The present study was undertaken to establish a simple and appropriate
method for fatty acids determination where samples are not submitted
to high temperatures during the preparative and quantification process
es. We describe an alternative method in which two techniques develope
d separately were combined: lipids saponification at low temperature a
nd underivatized fatty acids quantification by HPLC (high performance
liquid chromatography). Total lipids fraction was extracted from oils
and rat tissues using the Folch method. Lipids were saponified at 37 d
egrees C for 2 hours and extracted with hexane. Fatty acids were separ
ated in a reverse-phase column (C-8-Shimadzu) and identified by a refr
active index detector (RID-6A-Shimadzu). Fatty acid. composition of oi
ls (soybean oil, coconut fat and cocoa butter) and rat tissues (spleen
and thymus) was determined. The analysis of fatty acids using this me
thod was reproducible and the retention time, fatty acid recovery, min
imal detection limit were compared to gas chromatography. The advantag
e of this method is that during handling and detection, fatty acids ar
e not exposed to high temperatures, decreasing the possibility of its
oxidation and racemization. Therefore, this method is recommended when
fatty acids recovery is required.