Analysis of lipids by supercritical fluid chromatography

Sammanfattning: In this thesis is described the development of new metods for the analysis of triacylglycerols and fatty acid methyl esters by supercritical fluid chromatography. Packed micro columns have been utilized for SFC and the properties of different types of packing materials have been evaluated. For evaluation, columns were thus in situ impregnated with silver ions (argentation), permanganate, periodate and triazine-based dyes. Columns packed with silica particles have also been investigated. With all these phases, it appears that the silica surface residual silanols were deactivated with regard to interaction with solute molecules when small amounts of modifiers were added to the mobile phase. For elution of unsaturated compounds on silver impregnated columns, it was necessary to add a higher content of modifiers to the mobile phase in order to achieve a partial deactivation of the double bond/silver ion complexes. It was not possible to use a flame ionization detector with such mobile phases. Therefore an ultraviolet ( UV ) detector must be utilized for the detection, even though the responses for triacylglycerols and fatty acid methyl esters were strongly dependent on the number of double bonds. Excellent separations of triacylglycerols and of fatty acid methyl esters have been obtained. Further, the columns were extremely stable from a physical as well as from a chemical point of view.For quantitative analysis of saturated and unsaturated triacylglycerols a miniaturized evaporative light scattering detector ( ELSD ) for connection to packed micro columns SFC has been developed. This detector could be used with pressure programming and the detection limit was lower than 6 ng.