CHAPTER 9: Discrimination of Contraband Ivories Using Long Wavelength Portable Raman Instrumentation

Raman spectra of 33 specimens of terrestrial and marine mammalian ivory from an African elephant, hippopotamus, mammoth, pig, sperm whale and walrus along with two specimens of leopard teeth and two fake ivory samples, have been analysed using a prototype DeltaNu Advantage portable Raman spectrometer operating in the near-infrared region with a laser excitation of 1064 nm. The method of partial least squares discriminant analysis (PLS-DA) provided insights into separation of the Raman spectra collected from these ivories into species specific groups. Although the sample set was small, the findings indicate the potential development of robust supervised classification methods for the non-destructive, rapid, in-field forensic interrogation of seized contraband biomaterials at the source, as well as archaeological artefacts and museum collections. Such instrumentation would lead to faster decision making at the point of seizure, rather than sending the samples to laboratories for extensive chemical analysis.