Determination of phospholipids in biological samples by an improved densitometric method on thin-layer chromatograms

The quantitative determination of the different phospholipids present in samples of bile, liver or plasma has been performed by densitometric scanning of high-performance thin-layer chromatography plates. These have been developed as follows: pre-treatment with sulphuric acid-ethanol mixture, staining with ethanol-modified molybdenum blue reagent and post-treatments with water and ethanol added with a small quantity of sulphuric acid. The sequential treatment, which introduces some modifications in a previously described procedure, allowed a linear and stable colour response for phosphorous-containing lipids on uniform and colourless background. The calibration of each plate with standard mixture was required for obtaining results in good agreement with other routine methods of determination.