FTIR and¹³C NMR Spectrum Characterization and Significance of Amber from Different Origins

Some pieces of amber from different origins and copal resin were tested and analyzed by FTIR and¹³C NMR.From testing results，amber from difference origins has the basically similar FTIR characteristics，such as absorption bands at 2 930，2 870 cm^-1caused by the saturated C—H bond stretching vibration，and the corresponding infrared absorption bands 1 460～1 443 cm^-1and 1 384～1 375 cm^-1induced by CH₂—CH₃bending vibration. Compared with the amber，FTIR characteristics of copal resin show infrared absorption weak band at 3 080 cm^-1induced by C═CH₂antisymmetric stretching vibration，infrared absorption bands at 1 645 cm^-1induced by C═C stretching vibration and infrared absorption band at 890 cm^-1caused by C—H out of plane deformation vibration.Analyses of FTIR and ¹³C NMR characterize amber from different origins and natural resin with relative different petrochemical maturity degree. The age of amber from Burma，Dominica，Liaoning and Mexico reduce in turn．Peaks of ¹³C NMR spectrum at δ=14×10^-6～18×10^-6 and δ=179×10^-6～220×10^-6 only appear in copal resin，showing that the petrochemical maturity is relatively low．This paper finally concludes the FTIR and ¹³C NMR spectrum characterization and significance of amber from different origins．