1. Scope
1.1 These test methods cover the determination of phosphorus in unused lubricating oils and lubricating oil additives and their concentrates. The test methods are not restricted with respect to the type of phosphorus compounds that may be present - for example, trivalent or pentavalent phosphorus compounds, phosphines, phosphates, phosphonates, phosphorus sulfides, etc. - since all are quantitatively converted to an aqueous solution of orthophosphate ion by oxidation of the sample during the course of analysis.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.3 The values stated in SI units are to be regarded as the standard.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D3231 Test Method for Phosphorus in Gasoline
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D6299 Practice for Applying Statistical Quality Assurance Techniques to Evaluate Analytical Measurement System Performance
3. Summary of Test Method
3.1 Organic material in the sample is removed and the phosphorus is converted to phosphate ion by oxidation with sulfuric acid, nitric acid, and hydrogen peroxide. One of two procedures is then followed:
3.2 The photometric method is used where the phosphorus content is estimated to be under 2 %, and the gravimetric method is used for phosphorus contents of 2 % or over.
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. This test method is suitable for most applications requiring the determination of phosphorus.