1,721,344 research outputs found
Dalla diagnostica dei residui organici nei reperti archeologici sommersi alla ricostruzione di tecniche artigiane
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The importance of the scientific support to the preservation of cultural heritage: 1- Pollutants and organic materials in the Museum Environment
No full textMULTI-ANALYTICAL TECHNIQUES FOR THE STUDY OF PRE-COLUMBIAN MUMMIES AND RELATED FUNERARY MATERIALS
No full textDue to a paucity of original written information, we base our knowledge of the pre-Columbian civilizations of Latin America on archaeological and archaeometric analysis. Particularly, the analytical study of funerary materials collected by conquerors in historical times and archaeologists nowadays during their travels and expeditions contributes to a better understanding of religious practices and social organisation. In the present study, a multi-analytical approach is presented which was used for the characterisation of red and blue organic dyes, inorganic pigments and embalming materials in various archaeological finds from the necropolis of Anco`n (Peru). These included the funerary clothes belonging to a set of three mummies, dated between the 11th and the 13th century AD. Chromatographic and spectrometric techniques were used: high performance liquid chromatography with UV-Visible detector (HPLC-UV-Vis) for identifying organic dyes, scanning electron microscopy with energy dispersive X-ray spectrometer (SEM-EDX) for recognising pigments, and gas chromatography with mass spectrometric detection (GC/MS) for analysing organic embalming materials. This multi-analytical approach enabled us to characterise a range of materials. The presence of red anthraquinoid dyes and blue indigoid ones was assessed, although it was not always possible to identify the original source with certainty. Cinnabar was identified as the colouring material applied to one mummy’s hair. The molecular markers of conifer resin were detected in the bandages. The analytical results highlighted the use of a number of hitherto unknown dyes and embalming materials in Peruvian funerary rituals
GC–MS identification of proteins in wall painting samples: A fast clean-up procedure to remove copper-based pigment interferences
No full textA new approach was explored to purify proteins in a multi-step procedure for the characterisation of proteinaceous materials (casein, animal glue, and egg) in artwork samples by gas chromatography-mass spectrometry. High concentrations of inorganic salts, such as azurite, have been found to impair the determination of protein via amino acid analysis. The effect of varying concentrations of copper-based pigments on the quantification of amino acids was evaluated through the analysis of replica paintings prepared with the three types of proteinaceous materials. Glycine, aspartic and glutamic acids are the amino acids most affected by the presence of copper salts. In the case of high concentration of salts, this interference hampers the correct identification of the proteins. To eliminate the inorganic salts, a C18 pipette tip was used to clean-up the ammonia extracts before the acidic hydrolysis step. The clean-up procedure allows us to prevent the influence of the inorganic salts and thus allows correct protein identification, though the quantitative recovery of proteinaceous material is quite low. The effectiveness of the optimised procedure was evaluated by analysing samples from two Italian wall paintings from the 13th and the 14th centuries. Without the clean-up it would not have been possible to detect the presence of a mixture of egg and animal glue in one case, and that of egg in the other one
Polychlorobiphenyls (PCBs) in the environment: analytical procedures and data evaluation
No full textPolychlorobiphenyls (PCBs) have been produced since 1930 and exploited for a variety of purposes, including use in transformers, capacitors, paints, pesticides, and many other highly developed industrial activities. The high chemical and physical stability and the lipophilic characteristics of these compounds are responsible for their long-term persistence in the environment and for their ability to bioaccumulate. These reasons, along with the discovery of the widespread environmental occurrence of these pollutants and the possible connection of their presence to carcinogenesis, has led in the past few years to PCBs being included in the list of priority pollutants, thus making their monitoring in the environment and studies of their toxic effects on living organisms of prime importance. This paper describes analytical methodologies, interference elimination procedures, and quantitation criteria for PCB analysis in several different environmental matrices. The individual determination of non-ortho chlorinated congeners, whose toxicity factors are comparable with those of tetrachlorodibenzo-p-dioxins, and the application of supercritical fluid extraction and chromatography for their separation, and Fourier-transform infrared spectrometry for their identification are also discussed
CHARGE-TRANSFER ACROSS A POLYMER GEL LIQUID INTERFACE - THE POLYVINYL CHLORIDE+NITROBENZENE GEL WATER INTERFACE
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