Fourier transform infrared spectroscopy: a fast instrument test that passes infrared light through a thin film of oil and compares the absorbance spectrum against new oil. Specific bands reveal oxidation, nitration, sulfation, soot, glycol, water and fuel, plus depletion of additives such as ZDDP and phenolic antioxidants. It shines at trending and catching the wrong oil, and is weaker at absolute numbers.
FTIR shows a glycol peak, pull a coolant test on that engine before the rod bearings go.
Also heard as
- IR
- infrared analysis
Related terms
Oil analysis
Lab testing of in-service oil samples to judge oil condition, contamination and machine wear.
Antioxidant
Additive that slows the chemical aging of oil by intercepting the radicals and peroxides that drive oxidation.
ZDDP
Zinc dialkyldithiophosphate, the classic antiwear and antioxidant additive in engine and hydraulic oils.
TAN
Total acid number: milligrams of potassium hydroxide needed to neutralize the acids in one gram of oil.