editorial
Analytical Chemistry of Old, Precious Things
I
was privileged last month to attend the Workshop on Chemistry and Materials Research at the Interface between Science and Art. The workshop, organized by R. P. Van Duyne of Northwestern University and Marco Leona of the Metropolitan Museum of Art, was sponsored by the National Science Foundation (NSF) and the Arthur W. Mellon Foundation. It was attended by a range of chemists (many analytical, as you might expect), materials scientists, and scientists from conservation labs of institutions that house cultural objects (e.g., museums). The Freer Gallery, a leader among conservation science in the U.S., hosted one portion of the workshop; it was an elegant setting. An aim of the workshop was to craft information for and advice to the NSF in order to identify important problem areas in the study of artifacts and the means to restore or stabilize themOa subject that is called conservation science. The workshop revolved around three grand challenges: advancing analytical technologies; understanding material degradation; and developing methods for material stabilization, strengthening, monitoring, and repair. The first challenge, explicitly about analytical tools, permeated throughout the others. I was impressed with the level of analytical expertise within the conservation science community and with their passion for the subject. Consider: you are an analytical chemist faced with understanding color changes on a 500-year-old painting. The very old, unique sample needs an analysis of composition and structure without disturbing it, i.e., noninvasive measurements, desirably in its own quarters; you can’t “take it home to your lab”. You need to understand the chemistry occurring that causes the color loss. A hope of the workshop is that its report, the dialog with the participants, and the forming of further networks of conservation and analytical scientists will generate new collaborations and projects that broaden the base of research aimed at addressing the needs of conservation science. My goal in this Editorial is to promote awareness of the research opportunities to the analytical community. I would add that research in this area has a real and useful social impact because conservation of cultural objects allows the public to view them and rejoice in their beauty.
10.1021/AC9015165 2009 AMERICAN CHEMICAL SOCIETY
Published on Web 07/15/2009
Many more analytical needs were discussed than I can mention here. There is a major need for hyphenated imaging: not just images of elemental composition (such as by X-ray fluorescence and confocal X-ray fluorescence) or molecular character (such as by Raman microscopy, FTIR, or NMR), but of overlaid images of both classes of characterization, desirably in three, not just two, dimensions. There are issues of both spatial structure of the object (multiple layers of paints, binders, applied varnishes, and surface contaminants) and how the molecular and inorganic components interact with one another in degradation processes. Many of the pigments are particles of semiconductor materials (CdS) that in light can drive photochemical interactions with organic binders or other nearby pigment particles. What is the role of monolayers of surface water in transport in these processes? Another area of concern is the gradual oxidative breakdown of organic materials such as paper, parchment, leather, and textile materials. The organic structures are inherently polymeric; how do you determine how the degradation of the polymeric network affects the physical strength of the material? These are issues of substantial complexity. The focus of the workshop was more on conservation than discovery of history. Authors have published in Analytical Chemistry, for example, articles concerning ancient pottery and what it held (milk? beer? wine?), the provenance of maps (and fakes) from ancient times, the origins and ages of foodstuffs identified by their organic residues (such as lipids soaked into pottery), the ages and environments of fossil bones, and many more. Analytical Chemistry has welcomed and will continue to welcome quality research submissions in these areas and in the conservation of old, precious objects. The Editor applauds the efforts of the scientists working in those areas and urges others to consider them.
AUGUST 1, 2009 / ANALYTICAL CHEMISTRY
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