Response and linearity of different lipid compounds when analyzed by thin-layer chromatography with flame ionization detection.

The response an linearity were studied for about twenty different types of lipids in a quantitative thin-layer chromatographic system equipped with flame ionization detection (TLC-FID). For most compounds the response showed good linearity with loads from 0.4 to 15 micrograms. The relative response of cholesterol, sterol ester and wax ester in ratio to triglyceride was, however, found to depend on the concentration, and this should be taken into account in quantitative determinations. The relative response of different lipids varied from 0.6 for hydrocarbon to about 1.4 for cholesterol. The application of the TLC-FID technique for skin lipid separations is illustrated.