High-sensitive detection of Heritage Lakes via TLC-SERS Optochemical coupling

The analysis of organic dyes in historical artifacts is crucial for understanding ancient artistic techniques and conservation practices. However, the accurate identification of these dyes remains challenging because dye components in artworks are often highly complex and under certain spectroscopic analytical techniques, in particular of conventional Raman spectroscopy, their chromophoric molecules frequently generate strong fluorescence backgrounds that obscure the desired Raman signals. To overcome this limitation, thin-layer chromatography (TLC) was photochemically coupled with surface-enhanced Raman scattering (SERS) to establish an integrated separation and identification approach for the analysis of complex organic dyes. This strategy was applied to the investigation of anthraquinone-based red lakes extracted from ancient tapestries. The chromatographic separation step effectively reduced spectral interference arising from the coexistence of multiple components in the samples, thereby enabling the spatial separation of structurally similar dye species. Subsequently, silver nanoparticles were introduced to enhance the local electromagnetic field surrounding the chromophores. The Raman signals were amplified by several orders of magnitude, allowing the acquisition of clear and reliably assignable vibrational fingerprints. Experimental results demonstrate that the TLC–SERS approach enables the reliable identification of anthraquinone dyes in real historical textile samples, providing an effective experimental strategy for identification of related dyes in the field of cultural heritage conservation and restoration.