Nondestructive Discrimination of Biological Materials by Near-Infrared Fourier Transform Raman Spectroscopy and Chemometrics: Discrimination among Hard and Soft Ivories of African Elephants and Mammoth Tusks and Prediction of Specific Gravity of the Ivories

Abstract

This paper demonstrates the usefulness of near-infrared (NIR) Fourier transform (FT) Raman spectroscopy and chemometrics in nondestructive discrimination of biological materials. The discrimination among three kinds of materials—hard ivories, soft ivories, and mammoth tusks—has been investigated as an example. NIR (1064-nm) excited FT-Raman spectra were measured in situ for these materials, and principal component analysis (PCA) of the obtained spectra was carried out over the 1800–400-cm−1 region. The two kinds of ivories are clearly discriminated from one another on the basis of a one-factor plot. It was found that treatment of the Raman data by multiplicative scatter correction (MSC) greatly improves the ability to discriminate. Principal component weight loadings show that the discrimination relies upon the ratio of collagen and hydroxyapatite included in two kinds of ivories. The discrimination among the hard and soft ivories and mammoth tusks was made by a three-factor plot for FT-Raman spectra after the MSC treatments. Partial least-squares regression (PLSR) enabled us to make a calibration model which predicts the specific gravity of the hard and soft ivories.

Schreger pattern analysis of Mammuthus primigenius tusk: analytical approach and utility

“…Espinoza & Mann (1993), Fisher et al (1998, Palombo & Villa (2001), Trapani & Fisher (2003), and Lambert (2005) used Schreger pattern features, specifically Schreger angle values, to distinguish tusk dentin of various proboscidean species. Other workers interested in conservation and forensic questions have used trace element analysis (Prozesky et al 1995, Shimoyama et al 1998) and non-destructive Raman spectroscopy (Edwards et al 1997, Shimoyama et al 1997, Brody et al 2001 to distinguish tusks and artefacts of Loxodonta, Elephas, and Mammuthus from each other. Kautenburger et al (2004) used multi-element analysis by X-ray fluorescence for identification of ivory from various origins.…”

The Goodmanham plane: Raman spectroscopic analysis of a Roman ivory artefact

“…ž Since 'ivory' is a generic name for the exoskeletal growths of several mammals, the Raman spectra are actually very similar to each other, 8,9 consisting of phosphate and carbonate modes from the carbonated hydroxyapatite matrix and proteinaceous modes due to the collagen. The spectroscopic differences between the ivories of different mammalian species were only minor.…”

“…Raman spectroscopic biomarkers have been identified that distinguish bone from ivory in modern specimens, and the assignment of mineral inorganic and organic component bands has been accomplished. 7,8 There has been much interest in the non-destructive analysis of modern ivories, from a forensic and law enforcement standpoint, 9,16 and Raman spectroscopy has been adopted successfully for the discrimination between genuine and fake ivory materials in museum collections, including carved objects, netsukes and scrimshaw. 9,10 The use of portable Raman systems for the discrimination between mammalian ivories at airports to monitor illicit traffic in prohibited ivory products has been achieved 9 as a result of these recent studies.…”

Spectroscopic Discrimination of Bone Samples from Various Species

“…Here we report on a preliminary investigation of species differentiation based on Raman spectroscopy of bones. Our hypothesis is based on the literature which demonstrates that vibrational spectroscopic analysis of bone components and mineralized tissue can discriminate species of origin [24][25][26][27][28]. Species discrimination using Raman spectroscopy of animal tusk has been previously investigated by several researchers.…”

“…Dentine tends to be more mineralized and have less collagen than bone tissue. Shimoyama et al (1997) reports that hard and soft mammoth dentine were discriminated using near infrared (NIR) FT-Raman spectroscopy [24]. Brody et al (2001) report the discrimination of dentine from six mammalian species, with slight overlap, also using FT-Raman spectroscopy [26] and chemometeric processing.…”