A rapid sensitive method for determining phospholipid phosphorus involving digestion with magnesium nitrate

Abstract

Abstract A method is described for the rapid determination of phospholipid phosphorus in samples containing less than 0.5 μg phosphorus. Phospholipid phosphorus is first converted to inorganic phosphate by heating a dried lipid extract briefly over a Bunsen flame in the presence of magnesium nitrate, then dissolving the resulting residue in dilute hydrochloric acid at 95 C. The determination of the inorganic phosphate content of the sample then requires only the addition of Triton X‐100 and an acidic ammonium molybdate‐malachite green reagent. Absorbance is measured at 650 nm after 5 min at room temperature.