Surface-Enhanced Raman Spectroscopy: Using Nanoparticles to Detect Trace Amounts of Colorants in Works of Art

Abstract

In recent years, powerful physical processes occurring in the vicinity of nanoscale metal surfaces have been exploited in the art world for the detection of trace amounts of colorants with surface-enhanced Raman spectroscopy (SERS). With this technique, naturally occurring and man-made organic molecules used as dyes and pigments in objects from antiquity to the present day are being detected with high molecular specificity and unprecedented sensitivity. This chapter reviews the broad spectrum of SERS analytical methodologies and instrumental improvements that have been developed over the years in the field of cultural heritage science, and discusses significant case studies within different types of works of art and archaeological artifacts.

Improved spectral imaging microscopy for cultural heritage through oblique illumination

“…The only other technique currently capable of such sensitivity to organic-based colorants is surface-enhanced Raman spectroscopy which is usually limited to point analysis rather than the mapping demonstrated by our spectral microscope. (45) Lastly, the presence of ultramarine, indicated by the band at 630 nm, was also confirmed by Raman spectroscopy. The sparse modeling of pigment distributions in all the layers is shown in Figure 6.…”

Raman Spectroscopy of cultural heritage Materials: Overview of Applications and New Frontiers in Instrumentation, Sampling Modalities, and Data Processing

“…Although in recent years HPLC has significantly improved its detection limits for reduced sample sizes (of the order of 0.5 mm of dyed fibre and a few micrograms of samples from polychrome works of art), SERS maintains a sample-size and sensitivity advantage; in essence, if only one particle of colored pigment is visible, SERS can detect its colorant. However, compared to HPLC, this spectroscopic technique is severely limited in its ability to resolve complex mixtures of colorants [248,303]. To date, only a maximum of two dyestuffs have been detected in the same sample with SERS: madder and cochineal in red lake pigments used by painters in the Impressionist circle [247], cochineal and brazilwood in textiles from the early twentieth century atelier of Mariano Fortuny [159], and quinacridone combined with quinacridone quinone in commercial pigments [192].…”

“…Alternative methodological approaches to overcome this limitation have ranged from the simple combination of SERS with thin-layer chromatography (TLC) plates [37,53,148,246,251], to advanced analytical solutions involving consecutive UV laser ablation, deposition on a SERS-active support covered in silver nanoisland film, and analysis with an optical parametric oscillator (OPO) laser system [67], and hyphenated techniques coupling HPLC with SERS [314]. Surprisingly, the potential of combining microfluidic with SERS is still mostly unexplored in this field [248].…”

Raman Spectroscopy of cultural heritage Materials: Overview of Applications and New Frontiers in Instrumentation, Sampling Modalities, and Data Processing

“…Alternative methodological approaches to overcome this limitation have ranged from the simple combination of SERS with thin-layer chromatography (TLC) plates [37,53,148,246,251], to advanced analytical solutions involving consecutive UV laser ablation, deposition on a SERS-active support covered in silver nanoisland film, and analysis with an optical parametric oscillator (OPO) laser system [67], and hyphenated techniques coupling HPLC with SERS [314]. Surprisingly, the potential of combining microfluidic with SERS is still mostly unexplored in this field [248].…”