4.1 Some oils are formulated with organo-metallic additives which act as detergents, antioxidants, antiwear agents, and so forth. Some of these additives contain one or more of these elements: barium, calcium, phosphorus, sulfur, and zinc. These test methods provide a means of determining the concentration of these elements which in turn provides an indication of the additive content of these oils.

4.2 Several additive elements and their compounds are added to the lubricating oils to give beneficial performance (see Table 2).

1.1 These test methods cover the determination of barium, calcium, phosphorus, sulfur, and zinc in unused lubricating oils at element concentration ranges shown in Table 1. The range can be extended to higher concentrations by dilution of sample specimens. Additives can also be determined after dilution. Two different methods are presented in these test methods.

1.2 Test Method A (Internal Standard Procedure)—Internal standards are used to compensate for interelement effects of X-ray excitation and fluorescence (see Sections 8 through 13).

1.3 Test Method B (Mathematical Correction Procedure)—The measured X-ray fluorescence intensity for a given element is mathematically corrected for potential interference from other elements present in the sample (see Sections 14 through 19).

1.4 The preferred concentration units are mass % barium, calcium, phosphorus, sulfur, or zinc.

1.5 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.