Sulfates are formed as a result of the combustion of sulfur-containing fuels and can contribute to oil pollution and acid formation. This is particularly relevant in marine engines and diesel-powered plants.
Sulfate content is typically measured through FTIR or chemical digestion and titration. The amount provides a good measure of the stress the oil is exposed to.
The result is used to monitor oil aging and to assess the need for shorter oil change intervals, especially when using fuels with high sulfur content.