Headspace analysis of engine oil by gas chromatography/mass spectrometry

This study establishes the rationale necessary for determining the time to change engine oil. This is based on identifying gaseous components in new a nd used automobile lubricants, Key compounds, so-called "signature", are se parated and identified qualitatively by coupled gas chromatography/mass spe ctrometry, Volatile antioxidants at zero miles and fuel contaminants at low mileage are observed in the headspace of engine oil. Several oxidative deg radation components have been positively identified in the used oil, which include the following: acetaldehyde, acetone, butanal, 2-propanol, acetic a cid, 2-hexanol, benzoic acid, benzaldehyde, and 1-pentanol, This study stro ngly suggests that the status of lubricating oil can be determined by the a nalysis of the gas phase above the oil. Most importantly, it opens the poss ibility of performing conditional maintenance of the combustion engine base d on information obtained from gas sensors.