• Method adopted/last revised: 1998
• Method reapproved: 2014
• REF/ISBN: IP437-2936900
• Status: Current
• First printed in STM books: January 1998

Scope

This standard specifies a method for the determination of the concentration of eight elements commonly present in unused lubricating oils and additive packages, by inductively coupled plasma atomic emission spectrometry (ICPAES). The elements are barium, boron, calcium, copper, magnesium, phosphorus, sulfur and zinc. This standard is not applicable to used lubricating oils, where a wider range of elements may be present at low concentrations. Users should refer to ASTM D5185 for elemental analysis of used lubricating oils. Sulfur is included in the element range of this standard, but can only be measured on instruments that can operate at a wavelength down to 180 nm.

The precision statement was derived from laboratory samples of unused lubricating oils, and approximately 10 %(m/m) solutions of additive packages in white oil, that were diluted in a solvent containing an internal standard in a constant ratio of between 1 %(m/m) and 5 %(m/m). This procedure presents concentrations of additive elements and internal standard to the instrument generally in the 1 mg/kg to 100 mg/kg range. Both higher and lower concentrations of elements in samples can be measured by this 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 of analyte used for the calibration, and the sample dilution factor.

This standard can be used for the quality control of finished unused lubricating oils and additive packages to determine if the elemental composition meets specified limiting values.