Estimation of phosphatidylglycerol in fluids containing pulmonary surfactant

A simple, direct and non-destructive method for quantitative separation of phosphatidylglycerol from other phospholipids in pulmonary washings is described. Total lipid extracts from dog lung washings and phosphatidylglycerol standard were spotted quantitatively on chromatoplates and separated by one-dimensional thin-layer chromatography in chloroform-methanol-water 65:25:4 (v/v/v). Quantification was performed with Rhodamine 6G and fluorometry. Washings from eleven dogs contained (mean +/- S.E.) 236 +/- 25 microgram phosphatidylglycerol per g of parenchymal wet lung tissue which accounted for 8.7% +/- 2.3 of the total phospholipids. The procedure is especially useful for quantification of phosphatidylglycerol in microgram amounts.