Fluorescence spectroscopy applied in lubricant oils

In this work, we report the use of the fluorescence spectroscopy to identify lubricant oils. Optical characterization was performed in four commercial lubricant oils that are used in the reciprocating compressors. Mid-infrared absorption of samples indicates the presence of aromatic rings showing bands at 1605 cm-1 (C=C stretching) and 815 cm-1 (C–H stretch out of plane). UV-VIS absorption spectra show bands of di and polyaromatic rings (around 230 nm and 260 nm respectively). Exciting the samples at 360 nm, a broad emission band centred at 440 nm is observed, indicating that this excitation is appropriate to be used for the diagnosis of the oil presence in the environment.