Method for Determination of Lipin Phosphorus.

Abstract

Interest in the lecithin content of blood in syphilis necessitated an investigation of the various procedures for the estimation of phosphorus1-8 or more specifically, lipin phosphorus.2-6, It was found that “test tube” oxidations by H2SO and HNO3 had to be discarded. The danger of bumping with the small amount of reagents used became a source of great concern for micro-determinations.2-5, , , This led to the use of H2SO4 and H2O2 (suggestions of Baumann11 and Briggs). Digestions were greatly facilitated, but certain difficulties were encountered. The figures obtained were not constant and often too high, the variations depending on the amount of H2O2 employed. Blood (0.5 cc.) is pipetted into 10.0 cc. of an alcohol-ether mixture (3:1) contained in a 50 cc. volumetric flask, preferably fitted with a glass stopper, and brought to boiling by inmersion in a water-bath. Digestion is continued for about 3 min. After cooling, alcohol-ether is added to the 50 cc. mark and the whole shaken vigorously. The filtrate (25 cc.) is transferred quantitatively to a casserol of 150 cc. capacity and evaporated to dryness over a water-bath. Then 10 cc. of HNO3 (sp. gr. 1.42) is added and the dish rotated in such a way that the acid loosens the dried extract from the sides. 0.1 cc. H2SO4 (sp. gr. 1.84), 5 cc. KClO3 (saturated solution) and 4 cc. of a mixture of saturated KNO3, and a saturated solution of NaNO3 (1:1) are introduced. The casserol is placed in the oven at 85-95° C. and digestion continued until the mixture becomes white. A safe interval is about 20 hours. A longer period does not matter. The white crystalline residue is dissolved in water by heating over a small free flame and transferred to a centrifuge tube (15 cc.), Including at least 2 washings, the total volume should not exceed 10 cc.