Identification of Gear oil Additives

Verification of the presence of  various additives  in gear oils is often of  interest and different methods have been  suggested for the purpose. To identify dialkyldithiophosphate additives in lubricating oils, lewkowitsch  isolated  the  compounds in the form of copper salts. Paper  chromatography  was applied to the  identification of certain  anti-oxidants by Delves. Among the compounds  distinguished  were  diphenylamine, phenothiazine, and  phenyl alpha and  phenyl  beta  naphthylamines.