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 Hôpital 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 où la recherche se questionne sur la conservation des produits naturels, un projet intégré autour d’une pharmacopée ancienne permet d’allier conservation du patrimoine et avancée technologique. Il soulève une problématique à l’interface de la conservation-restauration, des sciences humaines et de la chimie dans le cadre de l’inventaire scientifique d’un ensemble de produits naturels appartenant à la collection de la pharmacie de l’Hôpital Sainte Marthe à Avignon.Cette officine offre un ensemble de substances naturelles d’un intérêt inestimable puisqu’une partie des produits a été conservée intacte depuis le XIXème voire même le XVIIIème siècle. Les études scientifiques réalisées sur cette collection autorisent l’évaluation de l’état de conservation des échantillons naturellement vieillis tout en renseignant sur les connaissances taxonomiques et pharmacologiques de l’époque.Les auteurs vous souhaitent une bonne lecture…

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 étude est d'établir une méthode universelle et non dénaturante pour caractériser les laques de garance par chromatographie en phase liquide (CLHP/UV-Vis.). Pour les analyser, les molécules anthraquinoniques doivent être décomplexées de leurs liaisons métalliques. Dans cette optique, deux procédés ont été améliorés, les ultrasons et les micro-ondes, associés à deux solutions, une solution d'acide oxalique (0,5 M dans MeOH / H2O 50/50) et une solution tampon d'acide acétique (1 M). Premièrement, la décomplexation d'une laque expérimentale d'alizarine a été optimisée par rapport à une méthode de référence utilisant un acide fort. Le procédé par micro-ondes utilisant l'acide oxalique a augmenté le rendement de décomplexation de l'alizarine (71%) par rapport à la méthode de référence (31%). Deuxièmement, différentes laques expérimentales de garance préparées en utilisant différents sels métalliques ont été décomplexés. Les résultats obtenus suggèrent que l'utilisation de micro-ondes associée à une solution d'acide oxalique est la méthode la plus universelle permettant une décomplexation des anthraquinones à partir de laques, sans hydrolyse des composés glycosidiques

GC-MS analyses from Roman Amphorae from Cosa in Etruria (Italy)

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GC–MS 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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GC–MS 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 l’art yoruba Enquête de terrain

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Analysis of balms taken from Egyptian human mummies using solid‐phase extraction and gas chromatography–mass spectrometry

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Anthropological and analytical studies of two Egyptian human mummies’ heads from Deir-el-Medineh

International audienceThis paper focused on a multidisciplinary study of mummification balms’ constituents from two Egyptian mummies’ 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 GC–MS 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