Photoacoustic investigation of copaiba oil

. In this study we demonstrate the usefulness of the Photoacoustic Spectroscopy (PAS) in the investigation of copaiba oil obtained from Copaifera tree, located in a site within Rondônia State, Amazon region, Brazil. Pure copaiba oil sample was diluted in 98% ethanol providing 10 different samples at volume concentration in the range of 5 to 50% vv. The observed photoacoustic spectral features from pure copaiba oil and the corresponding diluted samples, in the 0.18 to 4.00 μm wavelength region, are discussed in terms of five distinct bands (C, S, L, K, and X bands). Photoacoustic peak intensity was investigated as a function of the copaiba oil concentration in the 5 to 50% v.v.