In aggregation behaviors, there is an equilibrium between the solubilized monomers and the aggregated complexes, including self-assembled fatty acid vesicles. Previous experiments show that the concentration of fatty acid required to form vesicles is dependent on hydrophobicity of the fatty tail, ionic strength, and pH of the solution. Initially, fatty acids from 6 to 12 carbons were tested individually to determine the equilibrium between solubilized and aggregated fatty acid. Mixtures of chain lengths were then tested to determine effects of more complex and realistic systems. Aggregates were separated from the solubilized fatty acid using size dependent separations, such as equilibrium dialysis.<br/>After separation of aggregates from solubilized fatty acids, the fatty acids were derivatized in order for them to be sensed by gas chromatography with flame ionization detection (GC-FID). Fatty Acid Methyl Ester (FAME) derivatives were created using a Fischer esterification. Fisher esterification is a standard organic reaction, in which a fatty acid was heated in the presence of methanol and sulfuric acid to produce FAME. Fatty acids alone have too low of a vapor pressure to be characterized by GC, however the FAME is ideal for GC characterization. FID detection is quantitative and, in conjunction with an internal standard, gave reproducible concentration information for FAME. Generally FAMEs are made from biological lipids, which are longer and have some unstautated hydrocarbon chains. The method used was developed for shorter chain fatty acids.

Determination of aggregation equilibrium of fatty acid vesicles using gas chromatography with flame ionization detection

249th National Meeting (2015)

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