Code: TOF	Time Slot/Poster Number: 4:00 - 4:30 pm	Session: Art & Archeology I
Microanalytical and Non-Destructive Approaches for the Investigation of Works of Art by Surface-Enhanced Raman Spectroscopy (SERS)
Marco Leona1; John Lombardi2
1Metropolitan Museum of Art, New York, NY; 2City University of New York, New York, NY
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Summary
An improved SERS method involving resonant excitation, a highly active stabilized silver colloid (obtained by microwave assisted reduction of silver sulfate with glucose and sodium citrate), and pretreatment of the sample to maximize dye adsorption on the colloid has allowed us to identify organic colorants in works of art from samples as small as 25 micrometer in diameter. An alternative method employing a solvent saturated hydroxygel to extract microscopic amounts of a dye without disturbing the integrity of the work of art will be presented as well

Code: TOF	Time Slot/Poster Number: 4:30 - 5:00 pm	Session: Art & Archeology I
Surface Enhanced Raman Spectroscopy: a Minimally Invasive Tool to Assist in Authentication and Interpretation of works of art on paper.
Francesca Casadio1; Christa Brosseau2; Richard P. Van Duyne3
1Art Institute of Chicago, Chicago, IL; 2Saint Mary's University, Halifax, Nova Scotia, Canada; 3Northwestern University, Evanston, IL
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Summary
In this work, we describe direct, on-the sample, extractiveless application of citrate-reduced silver colloids to obtain high quality surface enhanced Raman spectra (SERS) of both natural and synthetic colorants used as lake pigments in important works of art on paper. Results from single grains of pigments in the watercolors of Winslow Homer (1836-1910) and a pastel sketch by Mary Cassatt (1844-1926) are discussed. The ultra-high sensitivity of SERS, combining exponential signal enhancement with simultaneous quenching of fluorescence, allowed acquisition of good quality spectra that enabled new insights onto the attribution and interpretation of the examined works.

Code: TOF	Time Slot/Poster Number: 5:00 - 5:30 pm	Session: Art & Archeology I
SERS of insoluble Synthetic Organic Pigments employing Calixarenes as dispersive Cavitands: Application to Quinacridone Quinone
Concepcion Domingo; Elena del Puerto; Santiago Sánchez-Cortés; José V. García-Ramos
Instituto de Estructura de la Materia, CSIC, Madrid, Spain
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Summary
High Performance Synthetic Organic Pigments are largely employed in modern art as well as in automotive paints, printing inks and coloration of plastics, rubber and textiles. Due to their high tinting strength, they are frequently present in relatively small quantities, then high sensitivity and selectivity analytical techniques are requested for their identification. SERS using colloid solutions could be one of the techniques of choice but many of them are insoluble, both in water and in organic solvents. We here present a new approach for getting SERS of Quinacridone Quinone in solution, employing Calixarenes as dispersive cavitands and hydroxylamine silver colloids.

Code: TOF	Time Slot/Poster Number: 5:30 - 5:50 pm	Session: Art & Archeology I
Raman Microscopy and the Identification of Pigments in Archaeological Artefacts
Robin Clark
University College London, London, United Kingdom
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Summary
Raman microscopy has proved to be a powerful technique for the identification of pigments on archaeological artefacts, thereby opening up a new dimension to their study. It is now often used in conjunction with other techniques such as X-ray fluorescence to complete the identification process. This survey of recent studies at UCL will embrace applications to stuccoes from Samara, Puebloan (Anasazi) ceramics, iron oxides in platinum coins, silver oxide/sulfide on silverware, Nasrid plasterware from the Alhambra, church mural paintings from the Pyrenees (including the characterisation of the blue mineral aerinite), and other current research.

Code: TOF	Time Slot/Poster Number: 5:50 - 6:10 pm	Session: Art & Archeology I
Micro-Raman Mapping on Conservation Science: First Results in Critical Issues
Claudia Conti1; Chiara Colombo1; Mauro Matteini3; Marco Realini1; Giuseppe Zerbi2
1CNR, Ist. per la Conserv. e la Valoriz. Beni Cult., Milano, Italy; 2Politecnico di Milano, Milano, Italy; 3Alma Mater Studiorum - Università di Bologna, Bologna, Italy
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Summary
In this study Micro-Raman mapping has been used to achieve direct information on critical issues in the field of conservation namely i) the penetration depth of protective and consolidant treatments applied on surfaces of works of art ii) the distribution of calcium oxalates in the naturally formed oxalate films found on the monument surfaces over centuries. Maps have been carried out on polished cross sections of two groups of specimens: painted plasters treated with ammonium oxalate solutions and oxalate films detected on carbonatic stones of monument surfaces. The method proposed is innovative in the field of conservation science.