Surface-enhanced Raman spectroscopy (SERS) in cultural heritage

Area of Science:

• Analytical Chemistry
• Art Conservation Science
• Spectroscopy

Background:

• Organic colorants in artworks often exhibit strong luminescence, hindering identification by conventional Raman microscopy.
• Surface-enhanced Raman spectroscopy (SERS) significantly amplifies Raman scattering from molecules on rough metal surfaces.
• SERS provides a viable alternative for analyzing strongly luminescent organic colorants.

Purpose of the Study:

• To detail the practical applications of SERS for identifying organic colorants in cultural heritage materials.
• To highlight the advantages of SERS over conventional methods for art analysis.
• To discuss the current limitations of SERS in this field.

Main Methods:

• Utilizing the surface-enhancement effect of rough metallic surfaces to increase Raman scattering intensity.
• Applying SERS to analyze organic colorants in various art forms like prints, drawings, paintings, and sculptures.
• Comparing sample size requirements with traditional techniques such as high-performance liquid chromatography (HPLC).

Main Results:

• SERS yields strong, clearly resolved spectra for organic colorants, enabling straightforward identification.
• The technique requires significantly smaller sample sizes (20-100 micrometres) compared to HPLC.
• SERS has proven effective for analyzing diverse cultural heritage materials.

Conclusions:

• SERS is a valuable and increasingly adopted technique for the identification of organic colorants in works of art.
• Its ability to analyze small samples and overcome luminescence issues makes it suitable for delicate cultural heritage objects.
• Further practical considerations and limitations are important for its effective application in art conservation.