IR spectrometry analysis

OELCHECK test instrument: PerkinElmer Spectrum One (fully automated)
Sample quantity: 5–15 ml for automatic machines, 1 ml for the ATR cell
Unit: A/cm (absorption based on 1 cm oil layer thickness)
% (if calculable)
Test result: Oxidation, nitration, sulphation, water, glycol, additive degradation, fuel, soot, FAME content (for diesel fuels)
Result range: - water: <0.1 - 5%
- glycol: negative/positive
- soot <0.1 - 10%
- oxidation: 0 - 40
- phenolic antioxidants: 0- 10 %
- vegetable oil: 1 - 20%
Analysis for: all oils and greases, diesel fuels
Brief description: The principle of FT-IR (Fourier-Transform-Infrared) spectroscopy is based on different molecules being present in the lubricant which, because of their typical chemical structures, absorb infrared light to different degrees with certain wavelengths. Changes in the used oil can be compared to the fresh oil reference spectrum and depicted, calculated and interpreted in the form of typical ranges for certain "wave numbers".
Statement: The infrared spectrum of a used oil sample provides information on impurities in the oil or changes compared to the spectrum of a fresh or reference oil. For example, oxygen compounds which have newly appeared in a sample indicate oil ageing. Changes to wave numbers which are typical for OH groups may be interpreted as water and given in %. Through comparison with the deposited spectra of fresh oil, the procedure also provides information reliably and quickly whether an unknown oil is a mineral oil, "bio-oil" or synthesis oil. Mixtures of various types of oil can also often be identified.
Underlying test standard:

DIN 51451, DIN 51452, DIN 51453, ASTM E2412

DIN EN 14078 (FAME content)