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.

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, and so forth-since all are quantitatively converted to an aqueous solution of orthophosphate ion by oxidation of the sample during the course of analysis.

1.2 The values stated in SI units are to be regarded as the standard.

1.3This 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.