Rapid Characterization of Proteinaceous Binders Used in Artwork and Cultural Heritage Materials by Surface-Enhanced Raman Spectroscopy (SERS)

The identification and characterization of binders in art and cultural heritage materials such as manuscripts, drawings, and paintings provide important information for dating, authentication, and conservation. However, the common methods are usually invasive and require micro-sampling. Here, a simple and rapid method was established based on surface-enhanced Raman spectroscopy (SERS) for quasi-uninvasive determination of proteinaceous binders with a portable Raman spectrometer. Initially, silica sol was prepared via a one-step synthesis and deposited on the germination paper to obtain a silica film. After being cut and wetted, 5-mm x 5-mm pieces of silica film were attached to the surface of the test object. The proteinaceous binders were extracted from the test objects with the interaction between silica, followed by SERS analysis using silver nanoparticles as the substrate. Scanning electron microscopic and optical microscopic images confirm that the surface of the samples was uninvasively damaged after extraction. The feasibility and reproducibility of this method were confirmed using paint models. The minimum detectable concentration of bovine serum albumin in the paint models was 0.005% (w/w). The method was successfully applied to determine the proteinaceous binders in fresh or aged paint replicas. Due to advantages that include rapid, quasi-non-invasive, and on-site analysis, this protocol is promising for the determination of proteinaceous binders employed in culture heritage materials.