Detection of Endangered Species Using the Agilent Resolve Raman Analyzer

Importance of the Topic

The illegal trade in wildlife parts is a multibillion-dollar activity that severely endangers species and undermines ecosystems. Rapid, reliable, and field-deployable analytical tools are essential for customs officers, law enforcement, and conservationists to identify trafficked animal products. Handheld Raman spectroscopy equipped with spatially offset Raman spectroscopy (SORS) offers a noninvasive approach to detect materials masked by coatings or packaging, enhancing on-site screening capabilities and supporting efforts to curb wildlife crime.

Objectives and Study Overview

This study evaluates the performance of the Agilent Resolve handheld Raman analyzer, integrating both traditional surface analysis and SORS through-barrier modes, for the identification of endangered animal products. The work aims to demonstrate: 1) the detection of ivory hidden under paint or varnish; 2) differentiation of authentic animal materials from plastic substitutes; and 3) classification of seized wildlife products into mineral-based and protein-based groups, with further differentiation using multivariate analysis.

Methodology and Instrumentation

The analyzer operates in two modes:

• Surface Raman mode for direct spectral acquisition of uncoated samples.
• SORS through-barrier mode to suppress surface interference and reveal subsurface spectra through colored plastics, paints, or varnishes.

Spectra were compared against the built-in Standard library, and custom libraries were created as needed. Protein-based samples were further analyzed using principal components analysis (PCA) to resolve subtle spectral differences arising from amino acid composition.

Main Results and Discussion

• Ivory Detection: Through-barrier SORS successfully recovered characteristic ivory Raman features beneath paint layers, while surface mode distinguished ivory from plastic imitations by their distinct spectral peaks.
• Sample Classification: Nine specimens (bone, ivory, teeth, armadillo scale, rhino horn, pangolin scale, seahorse, totoaba bladder, rhino toenail) were grouped:

• Mineral-based (hydroxyapatite rich): bone, ivory, teeth, armadillo scale – showed minimal spectral variation, requiring supplementary methods for precise identification.
• Protein-based (keratin rich): rhino horn, pangolin scale, seahorse, totoaba bladder, rhino toenail – exhibited amide bond signals common to proteins, with intensity differences linked to amino acid composition.

PCA of protein-based spectra produced clear clustering of pangolin, seahorse, rhino horn, and totoaba samples, demonstrating the method’s ability to differentiate among these high-value contraband materials.

Benefits and Practical Applications

• Rapid, on-site screening with under two-minute analysis times and no sample preparation.
• Noninvasive detection of concealed ivory and differentiation from synthetic substitutes.
• Capability to create custom spectral libraries for emerging or uncommon wildlife products.
• Deployable in border control, airports, and field sites for immediate enforcement decisions.

Future Trends and Opportunities

Advances in handheld Raman and SORS technology will further miniaturize instruments, improve sensitivity, and reduce analysis time. Integration with machine learning and expanded, cloud-based spectral libraries will enhance automated identification of new contraband types. Multimodal systems combining Raman with complementary spectroscopies or imaging methods may offer broader material coverage. Continued development will support conservation by enabling real-time monitoring of wildlife products and aiding forensic investigations.

Conclusion

The Agilent Resolve handheld Raman analyzer, leveraging both surface and SORS modes, provides a powerful, field-ready solution for detecting and classifying endangered animal products. It offers law enforcement and conservation agents a rapid, reliable, and noninvasive method to combat wildlife trafficking, differentiate authentic materials from fakes, and prioritize items for further laboratory analysis.

References

1. U.S. Immigration and Customs Enforcement (ICE), End Wildlife Trafficking, August 22, 2023.
2. Hong Kong Air Cargo Customs inclusion of Resolve for concealed narcotics and animal parts, Singtao, September 12, 2021.
3. Hargreaves M. et al., Application of Portable Raman Spectroscopy and Benchtop SORS to Concealed Biomaterials, J. Raman Spectrosc. 2009.
4. Movasaghi Z. et al., Raman Spectroscopy of Biological Tissues, Appl. Spectrosc. Rev. 2007.