Three commercial oil samples were analyzed with the use of the selectivity of resonance CARS. No fractionation procedures were used; the oil samples were simply dissolved in an appropriate solvent and pumped from 365 nm to 480 nm. All three samples could be differentiated by characteristic Raman bands at various pump wavelengths. In addition, comparisons between the CARS spectra of the oil samples and the CARS spectra of pure PAHs at the same pump wavelength yielded tentative identifications of perylene and benzo(ghi)perylene in two of the samples.
D. R. Van Hare, L. A. Carreira, and L. B. Rogers, "Coherent Anti-Stokes Raman Spectroscopy of Commercial Oil Samples," Appl. Spectrosc. 39, 347-352 (1985)