5.1 The composition of a lubricating oil has a large effect on the characteristics and uses of the oil. The determination of saturates, aromatics, and polars is a key analysis of this composition. The characterization of the composition of lubricating oils is important in determining their interchangeability for use in blending et cetera.

1.1 This test method covers the determination of total aromatics and total saturates in additive-free lube basestocks using high performance liquid chromatography (HPLC) with refractive index (RI) detection. This test method is applicable to samples containing total saturates in the concentration range of 74.9 % to 100.0 % by mass and aromatics in the concentration range of 0.0 % to 25.1 % by mass. The precision is expressed in terms of the total saturates.

1.1.1 Polar compounds, if present, are combined with the total aromatics. Precision was determined for basestocks with polars content <1.0 % by mass.

1.2 This test method includes a relative bias section for total saturates in basestocks based on a Practice D6708 accuracy assessment between Test Method D7419 and Test Method D2007. The derived correlation equation is only applicable for basestocks in the total saturates concentration range from 75.0 % to 100.0 % by mass as measured by Test Method D7419.

1.2.1 The applicable range for total saturates by Test Method D2007 is from 71.0 % to 99.0 % by mass as reported by Test Method D2007.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.