ASTM D4047 Test Method for Phosphorus in Lubricating Oils and Additives
ASTM D4047 Standard Test Method for Phosphorus in Lubricating Oils and Additives by Quinoline Phosphomolybdate Method
3. Summary of Test Method
3.1 Additive concentrates are diluted with phosphorus-free white oil to produce a working blend.
3.2 The sample is ignited with excess of zinc oxide whereby phosphorus is converted to phosphate. The residue is dissolved in hydrochloric acid and any sulfide formed is oxidized with potassium bromate. Phosphorus is then precipitated as quinoline phosphomolybdate and determined volumetrically by addition of excess standard alkali and back titration with standard acid.
4. Significance and Use
4.1 Knowledge of the phosphorus content, and thus the phosphorus-containing additives, in a lubricating oil or additive can be used to predict performance characteristics.
