28 research outputs found
Cultural Heritage Objects of Southern Benin: Plant Dyes and Exudates Used in Their Confection
Colors are practically ubiquitous in the artistic and craft objects of the South Benin region, affiliated to the Yoruba cultural area. Apart from the usual ochres and kaolin, the paint layers of the sculptures are little known, especially in terms of their binders but also plant dyes exploited. Colors from plants, usually used in textile dyeing or wickerwork, were among others also used in painting. The mid-term of research and analysis carried out in a multidisciplinary context provided information on the techniques formerly used by artists and craftsmen as well as on the original materials used. This information is inherent in a possible restoration of old museum objects
Inventaire scientifique de la pharmacie de l'ancien HĂŽpital Sainte Marthe d'Avignon
International audienceWhen the research comments on the conservation of natural products, here is an integrated project around an old pharmacopoeia allowing to combine heritage conservation and technological progress. It raises a problem at the interface of conservation-restoration, humanities and chemistry within the framework of the scientific inventory of natural products belonging to the collection of the pharmacy of the former Sainte-Marthe Hospital in Avignon.This pharmacy offers a set of natural substances of a great interest because the products were kept intact since the nineteenth or even the eighteenth century. The scientific studies carried out on this collection allow the evaluation of the state of conservation of the naturally aged samples while informing on the taxonomic and pharmacological knowledge of the period.The authors wish you a good reading.A l'heure oĂč la recherche se questionne sur la conservation des produits naturels, un projet intĂ©grĂ© autour dâune pharmacopĂ©e ancienne permet dâallier conservation du patrimoine et avancĂ©e technologique. Il soulĂšve une problĂ©matique Ă lâinterface de la conservation-restauration, des sciences humaines et de la chimie dans le cadre de lâinventaire scientifique dâun ensemble de produits naturels appartenant Ă la collection de la pharmacie de lâHĂŽpital Sainte Marthe Ă Avignon.Cette officine offre un ensemble de substances naturelles dâun intĂ©rĂȘt inestimable puisquâune partie des produits a Ă©tĂ© conservĂ©e intacte depuis le XIXĂšme voire mĂȘme le XVIIIĂšme siĂšcle. Les Ă©tudes scientifiques rĂ©alisĂ©es sur cette collection autorisent lâĂ©valuation de lâĂ©tat de conservation des Ă©chantillons naturellement vieillis tout en renseignant sur les connaissances taxonomiques et pharmacologiques de lâĂ©poque.Les auteurs vous souhaitent une bonne lectureâŠ
On the tracks of sandarac, review and chemical analysis
International audienceThe sandarac resin (Tetraclinis articulata) has been long used for its properties, mostly as a varnish component. Called juniper resin until the nineteenth century, the real botanical origin of sandarac is still unclear. The first approach to this issue is the review of the evolution of the etymology, terminology, and botanical description of sandarac through time. It seems that sandarac was mainly coming from T. articulata but the use of some juniper resins before the twentieth century is not to be excluded. The second approach is a chemical one; we used gas chromatography coupled to mass spectrometry to characterise the resin. As sandarac was the main component of the famous Italian varnish Vernice liquida, its characterisation is important for old paintings studies. However, although we could hope to differentiate sandarac, Juniperus communis and Juniperus oxycedrus resins by looking at their chemical composition, it appears that these resins are very similar. Besides, we notice a lack of old varnishes containing sandarac which complicates our work
Decomplexation de laques de garance avec l'emploi d'acide oxalique : une nouvelle méthode couplée aux micro-ondes ou aux ultrasons
International audienceThe aim of this study is to establish a mild extraction and universal method to characterize madder lakes of Rubia tinctorum by liquid chromatography (LC-PDA). In order to analyze the lakes, anthraquinone molecules must be decomplexed of metal links. To this end, two processes, one ultrasound and the other microwave, were improved, in association with two solutions, an oxalic acid solution (0.5M in MeOH/H2O 50/50) and an acetic acid buffer solution (1M). Firstly, the decomplexation of an alizarin experimental lake was optimized in comparison with a reference method using a strong acid. The microwave process used oxalic acid and increased the decomplexation yield of alizarin (71%), compared with the reference method (31%). Secondly, different madder experimental lakes which were prepared using different metal salts were decomplexed. The obtained results suggest that the use of microwave associated with oxalic acid solution is the most universal method providing a decomplexation of anthraquinones from lakes without hydrolysis of glycosidic compounds occurringLe but de cette Ă©tude est d'Ă©tablir une mĂ©thode universelle et non dĂ©naturante pour caractĂ©riser les laques de garance par chromatographie en phase liquide (CLHP/UV-Vis.). Pour les analyser, les molĂ©cules anthraquinoniques doivent ĂȘtre dĂ©complexĂ©es de leurs liaisons mĂ©talliques. Dans cette optique, deux procĂ©dĂ©s ont Ă©tĂ© amĂ©liorĂ©s, les ultrasons et les micro-ondes, associĂ©s Ă deux solutions, une solution d'acide oxalique (0,5 M dans MeOH / H2O 50/50) et une solution tampon d'acide acĂ©tique (1 M). PremiĂšrement, la dĂ©complexation d'une laque expĂ©rimentale d'alizarine a Ă©tĂ© optimisĂ©e par rapport Ă une mĂ©thode de rĂ©fĂ©rence utilisant un acide fort. Le procĂ©dĂ© par micro-ondes utilisant l'acide oxalique a augmentĂ© le rendement de dĂ©complexation de l'alizarine (71%) par rapport Ă la mĂ©thode de rĂ©fĂ©rence (31%). DeuxiĂšmement, diffĂ©rentes laques expĂ©rimentales de garance prĂ©parĂ©es en utilisant diffĂ©rents sels mĂ©talliques ont Ă©tĂ© dĂ©complexĂ©s. Les rĂ©sultats obtenus suggĂšrent que l'utilisation de micro-ondes associĂ©e Ă une solution d'acide oxalique est la mĂ©thode la plus universelle permettant une dĂ©complexation des anthraquinones Ă partir de laques, sans hydrolyse des composĂ©s glycosidiques
GCâMS and PCA analyses of diterpenoids degradation state in 21 human mummies of Ancient Egypt dating from New Kingdom to Graeco-Roman Period
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GCâMS and PCA analyses of diterpenoids degradation state in 21 human mummies of Ancient Egypt dating from New Kingdom to Graeco-Roman Period
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Couleurs et plantes colorantes dans lâart yoruba EnquĂȘte de terrain
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Analysis of balms taken from Egyptian human mummies using solidâphase extraction and gas chromatographyâmass spectrometry
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Anthropological and analytical studies of two Egyptian human mummiesâ heads from Deir-el-Medineh
International audienceThis paper focused on a multidisciplinary study of mummification balmsâ constituents from two Egyptian mummiesâ heads belonging to the Osteology collection of the Confluences museum in Lyon (France). These individuals come from the same necropolis, Deir el-Medineh in Upper Egypt. They were coated with particular substances not often encountered in studies of mummification balms. The objective was to identify the composition of the two types of samples found on each individual: an amorphous material resembling mummy balm and a sandy substance. The knowledge of the anthropology and the mummification practices associated to analytical chemistry study of the balms permitted to obtain a global characterization of these persons. The FTIR and GCâMS results notably permitted to observe (i) the presence of fat and beeswax within the amorphous black samples and (ii) the presence of natron, fatty matter and mastic resin within the sandy samples; these types of samplings are uncommon in ancient Egypt