Detecting Organic Dyestuffs in Art with SERS

Friday, 14 February 2014
Acapulco (Hyatt Regency Chicago)
Richard Van Duyne , Northwestern University, Evanston, IL
Title: Detecting Organic Dyestuffs in Art with Surface-Enhanced Raman Spectroscopy

R.P.VanDuynea, N.C. Shah a, F. Casadiob, G. Schatza,

a. Department of Chemistry, Northwestern University, 2145 Sheridan Road Evanston, Illinois 60208-3113

b. The Art Institute of Chicago, 111 S. Michigan Ave., Chicago, Il 60603-6110

Molecular characterization of organic compounds in mass-limited samples embedded in complex matrices remains one of the grand challenges of chemical measurements in cultural heritage science. Amongst these organic compounds, biomolecules derived from plant and animal sources and a wide variety of synthetic molecules have been used to impart color to textiles for thousands of years. Precipitated on colorless inorganic particles of calcium carbonate, alumina, clay or silica, these dyes have been used as pigments in easel paintings, illuminated manuscripts, watercolors, pastels, and a variety of other media, contributing to our artistic patrimony and cultural identity.  In the past few years Surface Enhanced Raman Spectroscopy (SERS) has been demonstrated as a powerful technique for the minimally invasive, ultra-high sensitive detection of both natural and synthetic organic colorants.  Dyes have successfully been identified in works of art from samples as small as a few grains (i.e. a few mg) of pigmented material or 25 μm of fiber using surface SERS.

In this talk, we report on the interdisciplinary efforts of a group of scientists at Northwestern University and the Art Institute of Chicago to develop tailored nanostructured substrates, experimental protocols, and most recently, theoretical approaches for dye identification.  The identification of colorants in important works of art on paper from America’s master watercolorist Winslow Homer (1836-1910) and pastels by American impressionist Mary Cassatt (1844-1926), as well as several examples of analysis of priceless textiles from the collection of the Art Institute of Chicago will be presented.  In addition, the underexplored area of infrared surface enhanced Raman spectroscopy (NIR-SERS) for analysis of artworks and the use of time-dependent density functional theory (TDDFT) for colorants’ identification will be presented.