Non-destructive methods to identify ivory from Proboscidea and to prevent wildlife crime, with a focus on handheld use

The potential of handheld, non-destructive devices for detecting ivory from Proboscidea is advancing rapidly. The elemental and structural composition of ivory provides insights into the animals' environments, living conditions, and origins, all of which are highly relevant to forensic science, conservation, and provenance research. This paper aims to provide a comparative literature review of studies on this topic, highlighting current trends and significant correlations. For this purpose, a review of the literature over the last ten years was conducted, with a particular focus on X-ray fluorescence (XRF), which has so far been the primary method used in research on the identification of ivory using handheld devices. As other methods, such as Raman spectroscopy, show promising potential for identifying ivory as well, results from handheld and benchtop instruments have also been included in this review, and the differentiation must be considered. Studies using handheld XRF analyze elemental composition and cover a broader range of topics, including distinguishing ivory from fake ivory, identifying carved ivory, detecting elemental differences in length and cross-section, and assessing sexual dimorphism, whereas research with Raman spectroscopy relies on vibrational modes and focuses more on species identification and age determination. In addition to XRF and Raman spectroscopy, complementary methods were reviewed, including Laser-Induced Breakdown Spectroscopy (LIBS) and Fourier Transform Infrared Spectroscopy (FTIR). Rather than providing an exhaustive overview, this review focuses on illuminating current trends and the most promising approaches in the field.