Asphaltene Content Testing
The asphaltene fraction is the most complex fraction in petroleum and it also has the highest molecular weight. The molecular structure contains hundreds and thousands of atoms. Asphaltenes in the form of asphalt or bitumen products are used in applications such as paving materials for roads or shingles for roofs. The exact molecular structure is very difficult to determine. Some of the more common analytical methods that used for asphaltene content include mass spectrometry, nuclear magnetic resonance, and SARA. Pentane insoluble constituents can be identified by membrane filtration. If by chance the lubricating oil has been exposed to high heat conditions then the toluene insoluble constituents of tar and pitch become more important. Toluene insoluble constituents can form from external sources, additives, fuel carbon, fuel degradation, or just engine wear in general. Changes in both pentane and toluene insoluble constituents can lead to lubrication deficiencies. Insoluble constituents that are identified can help assist in the performance evaluation of a used oil and help determine the cause of certain equipment failures. PhosLube Petroleum Laboratories has asphaltene content testing capabilities for lubricating oils and other petroleum products.