Determination of phospholipid phosphorus     Lipid sample in a glass pyrex tube (phosphorus free). Dry solvent.   Add 0.9 ml of 70% HClO4. Heat at 250°C for 25 min in a sand bath.   Let the tube cool down under a water stream.   Add 7 ml water.   Add 1 ml 2.5% ammonium molybdate. Stir.   Add 1 ml 10% ascorbic acid. Stir.   Heat in boiling water for 7 min.   Wait 10 min.   Read absorbance at 820 nm.       (Ref: Rouser, G., Fleischer, S. & Yamamoto, A. Lipids 8: 494-496, 1970)              Back to Protocols