Metropolitan Museum of Art

About: Metropolitan Museum of Art is a archive organization based out in New York, New York, United States. It is known for research contribution in the topics: Raman spectroscopy & Painting. The organization has 243 authors who have published 387 publications receiving 6043 citations. The organization is also known as: MMA & The Metropolitan Museum of Art.

Identification of organic colorants in fibers, paints, and glazes by surface enhanced Raman spectroscopy.

Abstract: Organic dyes extracted from plants, insects, and shellfish have been used for millennia in dyeing textiles and manufacturing colorants for painting. The economic push for dyes with high tinting strength, directly related to high extinction coefficients in the visible range, historically led to the selection of substances that could be used at low concentrations. But a desirable property for the colorist is a major problem for the analytical chemist; the identification of dyes in cultural heritage objects is extremely difficult. Techniques routinely used in the identification of inorganic pigments are generally not applicable to dyes: X-ray fluorescence because of the lack of an elemental signature, Raman spectroscopy because of the generally intense luminescence of dyes, and Fourier transform infrared spectroscopy because of the interference of binders and extenders. Traditionally, the identification of dyes has required relatively large samples (0.5−5 mm in diameter) for analysis by high-performance liqu...

Application of surface-enhanced Raman scattering techniques to the ultrasensitive identification of natural dyes in works of art

Abstract: Surface-enhanced Raman scattering (SERS) is a powerful technique for the detection of natural dyes found in archeological and historical textiles, in paintings, and in other works of art. Natural organic products historically used as textile dyes or lake pigments are often fluorescent under normal dispersive Raman measurement conditions. To add to the fluorescence problem, the amount of dye actually present on works of art is minimal, requiring extremely sensitive analytical techniques. The enhancement of the Raman signal and the quenching of the background fluorescence resulting from the adsorption of dye molecules on metal nanoparticles in SERS concur to solve the problems encountered when studying dyes by Raman spectroscopy. Reproducible spectra of several reference dyes were obtained, and extraction and adsorption protocols to optimize the analysis of samples from actual work of art were developed. SERS supports evaluated include citrate-reduced and hydroxylamine-reduced Ag colloids, as well as Tollens mirrors and silver nanoisland films. Dyes for which SERS spectra were observed include: alizarin, purpurin, laccaic acid, carminic acid, kermesic acid, shikonin, juglone, lawsone, brazilin and brazilein, haematoxylin and haematein, fisetin, quercitrin, quercetin, rutin, and morin. The incompatibility with SERS of techniques traditionally used to extract dyes from artwork samples was demonstrated, and a nonextractive hydrolysis technique specially suited to prepare SERS microscopic samples was developed. Finally, SERS was successfully used to identify alizarin in a 1mm by 50 µm (diameter) single fiber sample form a sixteenth-century tapestry. Copyright © 2006 John Wiley & Sons, Ltd.

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 μm 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 12th century polychrome sculpture from Auvergne, France).