Weena Sitthirakan. Development of high performance liquid chromatography for long chain fatty acids determination in environmental sample. Master's Degree(Applied Analytical and Inorganic Chemistry). Mahidol University. : Mahidol University, 2007.
Development of high performance liquid chromatography for long chain fatty acids determination in environmental sample
Abstract:
Fatty acids (FAs) occur widely in natural fats and dietary oil. They are also important as
nutrious substances and metabolites in living organisms. This work described the separation and
determination of five FAs including lauric acid, myristic acid, palmitic acid, stearic acid and
arachidic acid by HPLC with UV detection.
The absorbance of FA was enhanced by pre-column derivatization with phenacyl bromide
and naphthacyl bromide to obtain highly chromophoric derivatives. The wavelength at the
maximum absorbance of phenacyl ester and naphthacyl ester were 242 and 246 nm, respectively.
Various parameters that affected derivatization such as reaction time, reaction temperature and
amount of derivatizing agent were studied. The optimum condition of the HPLC system was 93:7
v/v MeOH:H2O with flow a rate of 1.0 mL/min. Detection limit was in the range of 7 to 42 and 6
to 12 ppb and were obtained from phenacyl ester and naphthacyl ester, respectively. The detection
of naphthacyl derivatives was shown to have a higher sensitivity than phenacyl ester. Thus, a
naphthacyl derivative is an optimum chromophore for fatty acid analysis.
The method was applied to determine fatty acid profiles in soil and liquid bacterial
culture. Liquid-Liquid extraction was employed for lipid removal. The separation of lipid classes
were performed using solid phase extraction with a aminnopropyl (NH2) cartridge. Phospholipid
fatty acids (PLFAs) were hydrolysed with potassium hydroxide and the FFAs extracted with
hexane. The optimum elution and loading were investigated. Phosphatidylcholine (PC) was spiked
in soil and liquid bacterial culture for investigation of recoveries of FAs from PLFAs. This
procedure gave a recovery of more than 79% (SD, 1.85 to 7.78 %).