A rapid and non-destructive identification method for tortoiseshell products using attenuated total reflectance infrared spectroscopy

Abstract

Tortoiseshell, traditionally made from Hawksbill Turtle (Eretmochelys imbricata) shell, has long been a popular material for the production of coveted ornamental items. Hawksbill Turtles are critically endangered and like all sea turtles the trade in their products (e.g., tortoiseshell) is illegal. Tortoiseshell objects are also produced from other species and plastics, so the identification of the tortoiseshell source is important for distinguishing illegally and legally traded items. Distinguishing faux and real tortoiseshell visually can be challenging, so a screening method using infrared spectroscopy has been developed to provide a rapid means of discriminating the source of objects. A non-destructive attenuated total reflectance sampling technique has been employed. Marine turtle, horn, casein, cellulose nitrate, cellulose acetate and polyester were identified as the materials used in tortoiseshell production by employing a visual comparison of their spectra. A simple method for the discrimination of the protein-based spectra produced by marine turtle, horn and casein objects is provided, enabling the source of such objects to be differentiated.