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Anglos D.,Foundation for Research and Technology Hellas | Anglos D.,University of Crete | Detalle V.,CNRS Research Laboratory for Historical Monuments
Springer Series in Optical Sciences | Year: 2014

A versatile spectrochemical technique enabling nearly instant, multi-element analysis of materials, LIBS is increasingly employed in studies of archaeological and historical objects, monuments and works of art. The development of several mobile LIBS instruments opens a lot more possibilities for analytical campaigns on site: at museums, conservation laboratories and even outdoors at excavation sites or historical monuments. The basic concepts underlying the use of LIBS in the context of cultural heritage studies are briefly reviewed along with technical and instrumentation aspects. Selected examples of analytical studies are discussed with emphasis on cases that demonstrate the use of mobile LIBS instruments. © 2014 Springer-Verlag Berlin Heidelberg. Source


Surowiec I.,Umea University | Nowik W.,CNRS Research Laboratory for Historical Monuments | Moritz T.,Swedish University of Agricultural Sciences
Dyes and Pigments | Year: 2012

Analysis of natural dyes in historical objects is important for both conservation purposes and to determine the origin and culture that produced it. Identification of a particular dye is usually made based on the presence of its main components, while consideration of minor components is important for differentiating between dyes originating from closely related species. Tyrian purple is one of the oldest dyes known to man and derives from different species of marine molluscs. In all of these species, indigotin, indirubin and their brominated analogues are the main colouring compounds. Here, we describe the identification of minor indigoids found in extracts of the pigment obtained from one of the Tyrian purple species, Hexaplex trunculus. Identification of these compounds was made based on isotopic patterns and accurate mass measurements of protonated molecular ions and their high collision energy fragments obtained in LC-MS/MS experiments. The unknown compounds appeared to be analogues of indirubin and its mono- and dibrominated derivatives with one CO group in the indirubin backbone substituted by a CNH group. Identification of these compounds facilitates the detection of dyestuffs from H. trunculus in historical objects and increases our knowledge about the dye biosynthesis and technology of Tyrian purple production. © 2012 Elsevier Ltd. All rights reserved. Source


Tong Y.,University Paris Est Creteil | Bouteiller V.,University Paris Est Creteil | Marie-Victoire E.,CNRS Research Laboratory for Historical Monuments | Joiret S.,University Pierre and Marie Curie
Cement and Concrete Research | Year: 2012

The aim of this study was to assess the efficiency of a realkalisation treatment using sacrificial anodes applied to reinforced concrete degraded by carbonation. Analytical determinations (acid/base indicators, quantitative pH, alkaline profiles, SEM and micro-Raman) together with electrochemical characterizations (rest potential, impedance, linear polarisation resistance and corrosion current densities) were performed on artificially carbonated slabs, before and after treatment (mainly 15 days, 11 weeks, 6 and 12 months). The treatment efficiency was demonstrated by an increase of pH and by an alkaline ion penetration in the concrete cover. Rest potential and corrosion current densities indicated a slight decrease of the rebar corrosion activity. Complementary Raman spectroscopy showed a change in the oxide species and SEM observations indicated that the cement matrix remained almost unchanged. © 2011 Elsevier Ltd. All rights reserved. Source


Nowik W.,CNRS Research Laboratory for Historical Monuments | Marcinowska R.,University of Warsaw | Kusyk K.,University of Warsaw | Cardon D.,University Lumiere Lyon 2 | Trojanowicz M.,University of Warsaw
Journal of Chromatography A | Year: 2011

Attempts at identification of mollusc species producing Tyrian purple from archaeological material are usually done with high performance liquid chromatography in the reversed-phase system, but the peaks obtained are often wide and asymmetric. This is due to the low solubility of the indigoids and their brominated derivatives in the mobile phase, especially 6,6′-dibromoindigotin, which is soluble in only few, particular solvents. Our study focused on improving both symmetry and peak height for more precise quantification. The influence of various factors was evaluated: stationary phase characteristics, mobile phase composition, elution gradient parameters and temperature on the peak shape of the main components of Tyrian purple. The best results were obtained using highly retentive, but moderately bonded ODS stationary phases (about 2.8μmolm-2), percolated with gradient of acetonitrile with acidified aqueous mobile phases (0.1% strong acid) at elevated temperatures (70°C). The upper quantification limit for 6,6′-dibromoindigotin was improved by over 350%, between standard and optimised systems. Using them, the detection and quantification of trace Tyrian purple components (less than 0.15%) aside from major indigoids becomes possible. Consequently, for the first time, the new analogues of brominated and unbrominated indirubins were found in the shellfish purple from Hexaplex trunculus. © 2011 Elsevier B.V. Source


Costa V.,Cercle des Partenaires du Patrimoine | Texier A.,CNRS Research Laboratory for Historical Monuments
Journal of Solid State Electrochemistry | Year: 2010

When restoring historical monuments, it is often verified that reinforcements, mostly made of ferrous alloys, are in quite a bad state and must be partially or totally replaced to prevent further degradation or accidents. Modern alloys such as stainless steels are increasingly used for such purpose, which raises the open question concerning their compatibility with the new types of sealing products available on the market. Even though it is not possible to use accelerated tests to give a livelong guarantee of adequacy of materials combination, electrochemical tests of metals in an aqueous extract of the sealing products could be used as screening to rapidly identify situations that would conduce to the premature corrosion of the metal. © 2009 Springer-Verlag. Source

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