• Method adopted/last revised: 2001
• Method reapproved: 2006
• REF/ISBN: IP368-2936900
• Status: Current
• First printed in STM books: April 2001

Scope

This method covers the separation and determination of representative saturated and aromatic components in lubricating oil basestocks that boil above 270 °C. All compounds that are more polar than saturates, including those that contain sulphur, nitrogen or oxygen, are determined as aromatics. Brightstocks may give low recoveries. This method may be applied to gas oils boiling in the range 200 °C to 350 °C by substituting pentane for hexane at all places in the text. Care is required during the solvent removal stage to minimise the loss of volatile sample components and maximise the sample recovery which should be greater than 95 % (m/m). Saturates [%/(m/m)] and aromatics [%(m/m)] should both be determined by gravimetry and the results normalized to 100 %. Report saturates, aromatics and recovery to the nearest 1 % (m/m).