A recent special issue in the Journal of Raman Spectroscopy explores advancements in Raman spectroscopy techniques, emphasizing mobile setups, data treatment, and novel applications in cultural heritage and forensic contexts. This collection of papers highlights the state-of-the-art approaches and the promising new perspectives they offer.
To push the boundaries of Raman spectroscopy, the Journal of Raman Spectroscopy has dedicated a special issue to "Advanced Raman procedures applied to natural/cultural heritage and forensic questions: Mobile set-up, data treatment and associated techniques." Spearheaded by researchers Maria Cristina Caggiani and Philippe Colomban from Sorbonne Université and CNRS in Paris, France (1), this issue aims to assess the current state of the field and highlight potential new perspectives. The papers in this special issue delve into innovative techniques that promise to enhance the application of Raman spectroscopy in various fields, particularly in cultural heritage and forensic analysis.
Details of the Work and Findings
The introduction to this special issue outlines several novel approaches grouped into key areas: application of multivariate statistical analysis to Raman spectra, use of mobile instrumentation directly in situ for both cultural and forensic contexts, tackling optics and spectral range issues, and coupling mobile instrumentation with other complementary analytical techniques. These advancements are crucial for analyzing valuable objects on-site, a necessity driven by regulatory constraints and the ethical considerations of preserving cultural heritage (1).
The expertise in analyzing objects of cultural heritage and the materials constituting them has a long history. With the rise of societal interest, recognized authorities have increasingly turned to scientific analyses to support or replace expert opinions. The miniaturization and cost reduction of instruments, including Raman spectrometers, have broadened their application, allowing even non-experts to perform these specialized analyses. However, compact devices often yield lower quality spectra, necessitating advanced data processing to compensate for these shortcomings (1).
Forensic applications face similar challenges, requiring non-invasive methods to study traces and comply with regulatory requirements. The coupling of Raman spectroscopy with portable X-ray fluorescence spectroscopy (pXRF) has proven beneficial in these contexts. This combination allows for the surface analysis of objects, providing valuable insights while preserving the integrity of the samples (1).
One significant optical challenge is the collection of scattered light from spots that cannot be reached by the operator. Stand-off Raman spectroscopy addresses this issue, making it particularly useful in forensic applications where contamination of the crime scene must be avoided, as well as in analyzing cultural heritage items like large wall paintings and architectural interiors (1).
The issue also explores the use of different spectral ranges to exploit information from photoluminescence (PL). Recent efforts have focused on making the best use of spectral information often considered as background noise. For example, a study analyzed six cobalt-based trademark pigments and two chemically pure compounds using a Raman spectrometer and a red He-Ne laser. The intense PL emitted by residual calcined alumina was detected quickly, demonstrating the potential of PL in Raman analysis (1).
Conclusion
The collection of papers in this special issue represents a significant step forward in the application of Raman spectroscopy. By integrating multivariate statistical analysis, mobile instrumentation, and novel optical techniques, these advancements offer new perspectives for studying cultural heritage and forensic evidence. The editors hope that this issue will inspire the Raman spectroscopy community to apply these advanced procedures and strive for further innovations in the field (1).
Reference
(1) Caggiani, M. C.; and Colomban, P. Advanced Procedures in Raman Forensic, Natural, and Cultural Heritage Studies: Mobile Set‐Up, Optics, and Data Treatment—State of the Art and Perspectives. Journal of Raman Spectroscopy 2024,55 (2), 116–124. DOI: 10.1002/jrs.6633
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