Discrimination of the Hard Keratins Animal Horn and Chelonian Shell Using Attenuated Total Reflection-Infrared Spectroscopy

Abstract

The ability to discriminate between objects manufactured from animal horn and chelonian (turtle, tortoise, or terrapin) shell is important from a cultural and archeological perspective such that it may allow conservators to determine the appropriate treatment and long-term care solution. It would also aid curators in identifying and cataloging items manufactured from these materials. Discrimination and classification is also a valuable tool for those involved in tracking the illegal trade in restricted materials of this nature. Attenuated total reflection infrared (ATR-IR) spectroscopy, using a single reflection diamond internal reflection element (IRE), coupled with discrimination analysis was used to analyze a total of thirty-nine samples (29 calibration samples, 10 validation samples). A discrimination analysis model was constructed using Mahalanobis distances to classify spectra into one of two classes. The model was then subsequently used to successfully classify all validation samples and correctly identify them as animal horn or chelonian shell based on second-derivative spectra of the amide I and II regions. This technique requires minimal to no sample preparation and may be used to nondestructively identify very small samples successfully without performing detailed secondary structural curve-fitting routines. This model should be a valuable resource to museums, conservators, and wildlife management programs for rapidly and reliably discriminating between animal horn and chelonian shell.

Creation of a peptide database of corneous beta-proteins of marine turtles for the identification of tortoiseshell: archaeological combs as case study

“…A variety of materials have been used to imitate tortoiseshell, such as paint and lacquers, resins, animal horn, gelatin films, casein formaldehyde and other synthetic and semisynthetic plastics [3][4][5]8,9,31,32]. Most current methods of analysis are limited to identifying true tortoiseshell from these imitations, and are typically based on spectroscopic methods such as Fourier transform Raman [33], and attenuated total reflection Fourier transform infrared (ATR-FTIR) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopies [34][35][36][37]. However, the exact taxonomy of the tortoiseshell sample cannot be achieved through these methods.…”

Pet fur or fake fur? A forensic approach

“…Crimes range from the abuse of illegal trade in protected species, or parts of them, such as horns, eggs [20] and tusks used to make ornaments or jewellery [21-26] or fur used to make gloves, hats and collars, to poaching and hunting out of season and many others. Italy was the first in Europe, and second in the world after the USA, to have imposed a ban on imports and the domestic trade of skins and furs from protected animals, firstly, through the ordinances of Dr Sirchia, the Minister of Health, issued in 2001 and renewed within two years, and then, in 2004, with the inclusion of the prohibition into the law against the mistreatment of animals [27].…”