A proposed ASTM International standard will be used to determine the total methyl hydrogen content of unadditized hydrocarbon-based lubricating base stocks. The test method uses high resolution nuclear magnetic resonance (NMR) spectrometers on samples that are completely soluble in chloroform at ambient temperature. ASTM’s petroleum products, liquid fuels, and lubricants (D02) is developing the proposed standard.

ASTM International is one of the largest voluntary standards developing organizations in the world.

“Methyl hydrogen content is a key compositional characteristic of hydrocarbon lubricating oils and can affect a variety of properties of the oil, including its boiling range, viscosity, low temperature flow, and oxidation stability,” says ASTM International member Frank Di Sanzo, a distinguished research associate at ExxonMobil Research and Engineering.

According to Di Sanzo, the proposed standard (WK73554) will continuously improve the approach of using compositional chemistry for determining the effects on lubricating oils. A Work Item (WK) is a proposed new standard or a revision to an existing standard that is under development by a committee. This work is being done by Subcommittee D02.04.0F on Absorption Spectroscopic Methods.

The new test method uses H-NMR technique to determine the methyl hydrogen content which is a characteristic likely applicable for base oil interchange.