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 etcetera.

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 aromatics in the concentration range of 0.2 to 46 mass %.

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

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

1.3 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.