Advancing Assessment of Subsurface Collagen Using NIR Spectroscopy

Archaeology seeks to uncover and interpret the past by examining material remains, offering insights into ancient civilizations, human behavior, and societal development. By studying artifacts and their contexts, researchers can understand cultural interactions, environmental changes, and lessons applicable to the present.¹

What role can spectroscopic techniques play in archaeological studies?

Spectroscopic techniques play a crucial role in this process, enabling precise analysis of elemental composition and site formation. These methods allow scientists to identify and characterize materials at a microscopic level, providing detailed elemental profiles of artifacts.¹ This analytical capability is essential for reconstructing the archaeological record and deepening our understanding of historical objects and the people that built the societies that produced them.¹

For example, a recent study developed near-infrared (NIR) spectroscopy as a rapid, non-destructive method to assess collagen preservation in archaeological bone.² Using partial least squares regression (PLSR) and random forest (RF) models, the research team predicted collagen content in archaeological bone, demonstrating how NIR was more effective at assessing collagen in bone, supporting high-throughput screening while reducing unnecessary destructive sampling for radiocarbon and isotopic analyses.^2,3

Why is near-infrared (NIR) spectroscopy the best technique to use for assessing collagen content in bones?

In the first part of our conversation with the study’s lead author Christina Macie Ryder, who is a postdoctoral researcher at the Center for the Study of the First Americans in the Department of Anthropology at Texas A&M University, she discusses why NIR spectroscopy is the preferred technique of choice in archaeology compared to mid-infrared (MIR) and Raman techniques. She explains that NIR’s penetration depth, which was several millimeters into bone, allows researchers to examine the bulk tissue rather than just the surface. Additionally, the non-destructive nature of NIR spectroscopy is crucial in archeology, as minimally invasive methods are often required to avoid damaging artifacts.

This interview is the first part of our interview with Ryder. Our exploration of the role of spectroscopy in archaeology will continue with a closer look at PLSR and RF modeling, which will be the subject of part two of our conversation with Ryder.

References

1. Wetzel, W. Spectroscopy Magazine Announces New Content Series Titled "Spectroscopy and Archaeology". Spectroscopy. Available at: https://www.spectroscopyonline.com/view/spectroscopy-magazine-announces-new-content-series-titled-spectroscopy-and-archaeology- (accessed 2026-03-27).
2. Ryder, C.; Celis, G.; Devièse, T. et al. Refining Near-infrared Spectroscopy for Collagen Quantification: A New Predictive Model for Archaeological Bone. J. Arch. Sci. 2026, 185, 106448. DOI: 10.1016/j.jas.2025.106448
3. Wetzel, W.; Spectroscopy Staff. Collagen Preservation in Archaeological Bone Using NIR Spectroscopy. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/collagen-preservation-in-archaeological-bone-using-nir-spectroscopy (accessed 2026-03-27).