| Two applications of comprehensive two-dimensional gas chromatography (GCxGC) were explored, one for the separation of mixtures of cis and trans octadecenoic (C18:1) fatty acid isomers, and the other for neutral lipid classes. Two methods were compared for separating C18:1 isomers: GCxGC and silver-ion high-performance liquid chromatography interfaced to atmospheric pressure photoionization ion (APPI) mass spectrometry. These methods were applied to the analysis of milk and beef fat. The GCxGC separation of neutral lipids allows separation of trace levels of lipids from the background components. This facilitates the quantification of target analytes and improves the performance of high-temperature gas chromatography since the column bleed and the analytes do not overlap. A mixture of ethyl oleate, triolein, and underivatized monoolein, and diolein were separated from the background and quantified. The method was applied to the analysis of the raw products of the enzymatic ethanolysis of canola oil. |
