1.1 This test method covers the quantitative determination of phosphorus in unused lubricating oils, such as International Lubricant Standardization and Approval Committee (ILSAC) GF 4 and similar grade engine oils, by inductively coupled plasma atomic emission spectrometry. 1.2 The precision statements are valid for dilutions in which the mass % sample in solvent is held constant in the range of 1 to 5 mass % oil. 1.3 The precision tables define the concentration ranges covered in the interlaboratory study (500 to 800 mg/kg). However, both lower and higher concentrations can be determined by this test method. The low concentration limits are dependent on the sensitivity of the ICP instrument and the dilution factor. The high concentration limits are determined by the product of the maximum concentration defined by the linear calibration curve and the sample dilution factor. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 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.