Microanalysis of organic pigments and glazes in polychrome works of art by surface-enhanced resonance Raman scattering

Abstract

Scientific studies of works of art are usually limited by severe sampling restrictions. The identification of organic colorants, a class of compounds relevant for attribution and provenance studies, is further complicated by the low concentrations at which these compounds are used and by the interference of the protein-, gum-, or oil-binding media present in pigment and glaze samples. Surface-enhanced resonance Raman scattering (SERRS) was successfully used to identify natural organic colorants in archaeological objects, polychrome sculptures, and paintings from samples smaller than 25 m in diameter. The key factors in achieving the necessary sensitivity were a highly active stabilized silver colloid, obtained by the reproducible microwave-supported reduction of silver sulfate with glucose and sodium citrate, and a non-extractive hydrolysis sample treatment procedure that maximizes dye adsorption on the colloid. Among the examples presented are the earliest so far found occurrence of madder lake (in a 4,000 years old Egyptian object dating to the Middle Kingdom period), and the earliest known occurrence in Europe of the South Asian dyestuff lac (in the Morgan Madonna, a 12 th century polychrome sculpture from Auvergne, France).archaeology ͉ dyes

Van Gogh’s Irises and Roses: the contribution of chemical analyses and imaging to the assessment of color changes in the red lake pigments

“…In the FTIR analysis of lakes, the presence of bands due to the binding media frequently interferes with the identification of the colorants, and the Raman spectroscopic analysis is often limited by the high fluorescence of most organic colorants. Surface enhanced Raman spectroscopy (SERS) gives good results in the analysis of red lake pigments and dyes, both in term of specificity and detection limit [4,5], nevertheless the technique has limitations for resolving mixtures of two or more colorants. High performance liquid chromatography (HPLC) is well established for identifying organic colorants in artworks because it permits not only a qualitative identification of the dyes, but also a quantitative estimation and, therefore, it is highly specific.…”

Laser Controlled Synthesis of Noble Metal Nanoparticle Arrays for Low Concentration Molecule Recognition

“…With the advent of portable Raman microscopy apparatuses, measurements can be performed in situ on micrometer-sized areas of the artwork. SERS applied to this kind of investigation opens the way to the detection of exiguous amounts of substances employed in the realization of the work of art [22]. In Figure 8, we report as an example SERS measurements performed on a silver substrate soaked in a 10 −4 M concentrated aqueous solution of alizarine.…”

In SituDetection of Acid Orange II in Food Based on Shell-Isolated Au@SiO2Nanoparticle-Enhanced Raman Spectroscopy

“…表面增强拉曼光谱/技术(Surface Enhanced Raman Scattering, SERS) [6,7] , 因其样品制备简单、易于操作、并 且对样品损伤小等优点, 在拉曼标记 [8] 、化学反应过程 原位监控 [9] 、文物鉴定 [10] 、国土安全以及化学/生化分析 中发挥着日益重要的作用 [11] . 近年来便携式拉曼光谱技 术的进一步发展使得该技术有望在食品中非法添加剂 的监测和污染物的现场分析方面获得应用 [12,13] .…”