GCMS Determination of Free Fatty Acids in the Presence of Triglycerides

The goal of the study was to investigate the kinetics of the esterification reactions of triacylglycerides (TAGs) and free fatty acids (FFAs). TAGs and FFAs are lipids that are produced in biological systems and have high production rates in several organisms, including algae. With an increasing push toward renewable energy and clean energy, there is an interest in biofuels. Algae is found to produce high amounts of TAGs and lower amounts of FFAs, both of which can be esterified to fatty acid methyl esters (FAMEs). FAMEs can be used as a feedstock for biodiesel, gasoline, diesel, jet fuel, etc.. The ratio of TAGs and FFAs in different species of algae can vary based on growth and harvesting conditions. Since FFAs and TAGs are both esterified to FAMEs, the quantification of TAGs cannot be based on the production of FAMEs alone. TAGs and FFAs exhibit different reaction rates based on both time and temperature. The reaction rates of FFAs are faster at both lower times and temperatures than TAGs. The objective was to measure the reaction rates of FFAs at various times and temperatures to develop a method to determine the amount of TAGs produced by algae. The results of the experiments showed that the method was unable to differentiate between FFAs and TAGs, because the unsaturated compounds were still converting at low temperatures and times. The goal for future work is to use a titration with a strong base to analyze the FFA content found in a mixture.