CONICET | Buscador de Institutos y Recursos Humanos

The chemical investigation of museum collection items can provide key information on theprovenance and technical aspects involved in their production and, additionally, can help in theestablishment of restoration and conservation strategies of rare or valuable assets. Naturalorganic materials are challenging because of their chemical complexity and expecteddegradation. In this work eight ethnographic resins from different sites in the Amazon andcentral areas in Brazil were studied by FT-Raman spectroscopy aiming at the non-invasive andnon-destructive identification of their chemical composition; chromatographic methods (TLCand GC-MS) were used as destructive confirmatory techniques. The samples were classifiedinto five groups, each one presenting a common set of spectroscopic features: diterpenoid resinswith chemical composition similar to the Brazil copal in some cases with carotenoids in theircomposition as did the triterpenoid resins also identified. Additionally, two gums(polysaccharides) were detected and two very dark samples only generated a thermal or aluminescent background (1064 nm and 785 nm excitation, respectively). Total ion current (TIC)chromatograms from these very dark samples only showed peaks assigned to fatty acidsprobably because the resinous compounds were not soluble in the solvent used in CG-MSanalysis. These results show that resin-containing museum assets in the Brazilian ethnographiccontext can be studied directly by Raman spectroscopy, contributing to a better understand ofIndian groups culture (resin provenance, uses and processing for example). The results will beused as a database to be compared with certified reference samples, when available.

enviar mensaje