The refractive indices (RI) of the eight samples of copaiba oils, collected for this study at RDS Tupé ranged from 1.50284 to 1.50786. The thin layer chromatography (TLC) plates of these oils revealed with anisaldehyde-sulphuric acid reagent showed dark lilac stains with several small stains at low Rf and a large rounded stain at high Rf. On the other hand, the twelve copaiba oils purchased at local markets presented RI between 1.48176 and 1.50886, and the TLC plates, showed as general profile blue stains, with smaller superimposed stains at low Rf, bigger superimposed stains like elongated stain at high Rf and a colorless rounded stain at middle Rf. Among 12 purchased oils at local markets, a) three oil-resins presented similar RI and TLC profile to those observed for collected copaiba oils; b) six oils showed same RI and TLC profiles to those observed for soybean oil; c) three samples presented RI near to those showed by copaiba oil-resin, however the TLC profile was near to profile observed for a prepared mixture soybean oil: copaiba oil, two samples with 3:1 proportion and one sample with 1:3 proportion. Therefore, the RI determination and the TLC profiles could be considered rapid and efficient procedures for detection of vegetal oil in the copaiba oil-resins.
Copaifera multijuga; Fabaceae; copaiba oil-resin; refractive index; thin layer chromatography
