Raman spectra and ab-initio calculations in Bertholletia excelsa oil

In the Brazilian Amazon, many plants are important in the economic context, since they can be obtained from raw material for the most diverse commercial applications. Oils extracted from plants in general are in this context. Bertholletia excelsa produces one of the best-known fruits of the Amazon, the Brazil nut, from which the oil of the same name is extracted, object of study in this work. In the present work the vibrational study of the oil of Brazil nut was performed by Raman spectroscopy (RS), since it is a technique of rapid evaluation in the physical-chemical study, since any preparation of the sample is excluded and can be performed often on-site, and with as little time as possible. For the analysis, a monochromatic source Raman spectrometer with excitation frequency of 633 nm was used. In addition, the spectral formation was discussed based on the chemical composition of the sample by density functional theory (DFT) in order to compare and understand the vibrational nature of the sample. The results showed intense vibrational bands from fatty acids with C-C, C=C and O-H bonds. A brief approximation with calculated first principles was used to predict results. The present work also aims to show that RS technique contributes in a safe and fast way for qualitative analyzes in natural oils.