Isotopic analysis of lead present in the cinnabar of Roman wall paintings from the Xth Regio "(Venetia et Histria)" by ICP-MS

The analysis of Roman wall paintings coming from Verona, Vicenza, Padova, Pordenone and Trieste evidentiated the presence of cinnabar. In this work, the isotopic composition (206)Pb, (207)Pb and (208)Pb of trace of lead present in cinnabar is reported, via ICP-MS measurements. The isotopic ratio values are compared with the values obtained from samples coming from Roman wall paintings of Pompeii and from the mines of Almaden (Spain) Monte Amiata (Grosseto Italy) and Idria (Slovenia). All the isotopic data can be represented by a "field" ranging from Huelva, to Almeria Spanish provinces. This trend could be due to the mixing of cinnabar products treated in Rome.     

Micro-Raman spectroscopic investigation of external wall paintings from St. Dumitru’s Church, Suceava, Romania

The external sixteenth century wall paintings of St. Dumitru's Church in Suceava (Romania) are suffering visually from deterioration. Fragments of these paintings spallated from the external wall have been studied by micro-Raman microscopy in order to elucidate possible causes of this process. Calcite and alpha-quartz are the components of the substratum indicating that the artists used the Roman fresco technique comprising a limewash putty. No organic binders have been detected in the substrate or pigment application. Amorphous carbon and goethite, alpha-FeOOH, have been identified in areas containing residues of grey and yellow pigments, respectively. Small amounts of gypsum have been detected in the grey areas which we attribute to special attention being given to surface preparation and pigment application in these areas. An abundance of sodium nitrate, nitratine, microcrystals have been observed on the surfaces of many fragments which suggests that a biodeterioration process originating from guano deposits could have been operating in these frescoes.     

A Comparative Study of Pigments from the Wall Paintings of Two Greek Byzantine Churches

The goal of this study was to characterize pigments used in the murals of two Byzantine churches, from Kastoria, northern Greece. The identification of the iconographer was also investigated by comparing the pigments applied in the wall paintings of the churches. Pigment microsamples of various colors were collected and analyzed by environmental scanning electron microscopy coupled with an energy dispersive system to characterize the elemental composition. Raman spectroscopy was employed to collect molecular spectra for characterization of mineralogical phases. Hematite, cinnabar, and minium were identified in red surfaces. Brown and yellow colors were assigned to mixtures of iron oxides, iron hydroxides, and calcite. Mixtures of iron, lead, and mercury compounds were used to produce different hues in the murals. Black tones were prepared primarily using charcoal and bone black. Grey colors were produced by a mixture of black carbon with calcite; blue hues, by a mixture of iron oxides, calcite, and black carbon. The minerals used were similar for both churches. However, the green color was prepared either by green earth or mixtures of iron oxides and calcite. A modern pigment, lithopone, was also determined, demonstrating restoration or overpainting and thus complicating possible correlations. Based on these preliminary results, the wall paintings could not be ascribed to a specific iconographer.     

Use of different spectroscopic techniques in the analysis of Roman age wall paintings

In this paper the analysis of samples of Roman age wall paintings coming from: Pordenone, Vicenza and Verona is carried out by using three different techniques: energy dispersive x-rays spectroscopy (EDS), x-rays fluorescence (XRF) and proton induced x-rays emission (PIXE). The features of the three spectroscopic techniques in the analysis of samples of archaeological interest are discussed. The studied pigments were: cinnabar, yellow ochre, green earth, Egyptian blue and carbon black.     

Analysis of Roman age wall paintings found in Pordenone, Trieste and Montegrotto

The aim of the present work is the study of many fragments of wall painting from archaeological excavations in three different Roman age sites dating back to the I Century before Common Era: Pordenone (località Torre); Trieste (Crosada) and Padova (Montegrotto). The techniques used were optical microscopy, scanning electron microscopy (SEM), equipped with a EDS microanalysis detector, X-rays powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Fourier transform Raman spectroscopy (FT-Raman) and electron paramagnetic resonance (EPR) spectroscopy. The identified pigments were: cinnabar, hematite, celadonite, glauconite, cuprorivaite (Egyptian blue), yellow and red ochre, calcite, limonite, coal black.In general, the mortar preparation did not correspond to the complex procedure suggested by Vitruvius (De Architectura), but generally showed a porous layer, with crushed grains under the pigment layer. In some cases, two superimposed pigment layers were found: yellow superimposed on both red and pink, black on pink, green on black.The slight differences we found in the use of the pigments in the three studied sites might show that the same technology, culture and taste spread all over the Roman Empire in North Eastern Italy (X^a Regio Venetia et Histria).     

FT-Raman spectroscopic analysis of pigments from an Augustinian friary

The Raman spectroscopic analysis of several stone samples with applied red pigments obtained from an archaeological excavation of an Augustinian friary discovered during the construction of an extension to Hull Magistrates Court in 1994 has revealed a surprising diversity of composition. Cinnabar, red lead and haematite have all been identified alone or in admixture; the cinnabar is exceptional in that it has only been found heavily adulterated with red ochre and red lead, as the other two pigments are found alone. There are signatures of limewash putty, which has been applied to the stone substrate prior to the painting, which is characteristic of the Roman method of wall painting, and there are no traces of gypsum found in the specimens studied. This evidence indicates an early mediaeval method of stone decoration.     

Electrochemical Characterization of Egyptian Blue Pigment in Wall Paintings Using the Voltammetry of Microparticles Methodology

The solid state voltammetric response of Egypt blue, Han blue and ploss blue pigments upon attachment to graphite electrodes in contact with aqueous phosphate buffer at pH 7.0 is studied by voltammetry of microparticles and scanning electrochemical microscopy. Such voltammetric responses, combined with those for synthetic specimens consisting of binary mixtures of the pigment and SiO₂ or CaCO₃ as well as ternary ones of CaCO₃ and SiO₂ mixtures allow for the identification of the pigment and the support in samples from wall paintings using different electrochemical parameters, in particular upon performing the Tafel and modified Tafel analysis of voltammetric peaks. Identification of Egypt blue in microsamples of murals from a Roman archaeological site in Castulo (Jaén, Spain) is discussed.     

Byzantine wall paintings from Mani (Greece): microanalytical investigation of pigments and plasters

The present case study concerns the technology of Byzantine wall paintings from the Mani Peninsula, Greece. An assemblage of 12 Byzantine churches, constructed in the tenth to fifteenth century, was included in an initial analytical survey. Two random samples of wall paintings were taken in each monument in order to study their micro stratigraphy and the composition of pigment and plaster layers. Polished sections were fabricated for examination with optical microscopy and scanning electron microscopy (SEM). Furthermore, selected samples were powdered and analysed with Fourier-transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The analytical results achieved in this case study provided general conclusions concerning painting techniques for wall paintings in a rather provincial area of the Byzantine Empire. The palette comprised mainly earthen pigments like ochres and carbon black but occasionally also other pigments like cinnabar, minium and ultramarine. In view of future studies, a portable X-ray fluorescence analysis (XRF) set-up was tested.     

Study of mural paintings using in situ XRF, confocal synchrotron-μ-XRF, μ-XRD, optical microscopy, and SEM-EDS--the case of the frescoes from Misericordia Church of Odemira

In this work, we present the results of an analytical method developed for detailed pigment identification, stratigraphy, and degradation of the paint layers of mural paintings applied in the study of the 17th century frescoes from the Misericordia Church of Odemira (Southwest Portugal). In situ X-ray fluorescence spectrometry analyses were performed on three panels of the mural paintings and complemented by colorimetric measurements. The different color areas were also sampled as microfragments (approx. 1 mm2) that were studied as taken or mounted in epoxy resin to expose the different paint layers. The microfragments of paint layers and their cross sections were characterized by optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray spectrometry. Furthermore, elemental analysis was obtained with spatially resolved confocal synchrotron radiation μ-X-ray fluorescence spectrometry performed at ANKA synchrotron FLUO beamline. Occasionally, phase analysis by μ-X-ray diffraction was also performed. Results from the different techniques allowed pigment identification and, in some cases, the evaluation of color changes due to degradation processes and, considering the Southern Portugal geology, the identification of their possible provenance. The pigments used were essentially yellow, brown and red ochres, smalt blue, copper green, and black earths, probably from local sources.     

Investigation and analysis of Ryukyu lacquerwares decorated with wisteria vine by pyrolysis GC/MS and 87Sr/86Sr isotope ratio

Three lacquer trays decorated with wisteria vine (rattan) produced in the 18–19th century in Ryukyu Kingdom were analyzed by cross‐section, pyrolysis gas chromatography/mass spectrometry, strontium isotope ratios (⁸⁷Sr/⁸⁶Sr), radioactive carbon‐14 dating, and field emission scanning electron microscope with energy dispersive X‐ray spectrometry. One sample had only one red lacquer layer, and the other two samples had two layers with top red lacquer and a bottom layer of natural lacquer, respectively. The ⁸⁷Sr/⁸⁶Sr isotope ratios of three samples were 0.7091–0.7107, consistent with that of the Japanese mainland (<0.7110). The wood species of lacquer objects were identified as Japanese white pine, Japanese cedar, and Cunninghamia lanceolata, which grow in the Japanese islands. The carbon‐14 dating results showed that the lacquer films were about 1719–1785. In pyrolysis gas chromatography/mass spectrometry, 3‐heptylphenol (C7) and 3‐pentadecylphenol (C15) were detected in the mass chromatograms at m/z = 108 and palmitic acid and stearic acid were detected in the mass chromatograms at m/z = 60, implying that the coating material was sap collected from Toxicodendron vernicifluum lacquer tree and included a drying oil. Energy dispersive X‐ray spectrometry revealed that mainly mercury sulfide was used as red pigment in these three Ryukyu lacquerwares. Copyright © 2017 John Wiley & Sons, Ltd.     

Development of a species-specific isotope dilution GC-ICP-MS method for the determination of thiophene derivates in petroleum products

A species-specific isotope dilution technique for accurate determination of sulfur species in low- and high-boiling petroleum products was developed by coupling capillary gas chromatography with quadrupole ICP-MS (GC-ICP-IDMS). For the isotope dilution step ³⁴S-labeled thiophene, dibenzothiophene, and mixed dibenzothiophene/4-methyldibenzothiophene spike compounds were synthesized on the milligram scale from elemental ³⁴S-enriched sulfur. Thiophene was determined in gasoline, ‘sulfur-free’ gasoline, and naphtha. By analyzing reference material NIST SRM 2296, the accuracy of species-specific GC-ICP-IDMS was demonstrated by an excellent agreement with the certified value. The detection limit is always limited by the background noise of the isotope chromatograms and was determined for thiophene to be 7 pg absolute, which corresponds to 7 ng sulfur/g sample under the experimental conditions used. Dibenzothiophene and 4-methyldibenzothiophene were determined in different high-boiling petroleum products like gas oil, diesel fuel, and heating oil. In this case a large concentration range from about < 0.04 to more than 2,000 μg g⁻¹ was covered for both sulfur species. By parallel GC-ICP-MS and GC-EI-MS experiments (EI-MS electron impact ionization mass spectrometry) the substantial influence of co-eluting hydrocarbons on the ICP-MS sulfur signal was demonstrated, which can significantly affect results obtained by external calibration but not those by the isotope dilution technique.     

Analysis of pigments from Roman wall paintings found in Vicenza

The analysis of about 60 samples of wall paintings was carried out using different chemicophysical techniques: optical microscopy, scanning electron microscopy (SEM) equipped with an EDS microanalysis detector, X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The identified pigments were cinnabar, hematite, red ochre, celadonite, cuprorivaite (Egyptian blue), yellow ochre, goethite and carbon. Only in one case some lead white was found instead. In general, the mortar preparation did not correspond to the complex structure suggested by Vitruvius (De Architectura), but it generally showed a porous layer, with crushed grains under the pigment layer. In certain cases two superposed pigment layers were found: yellow superimposed on both red and pink, black on pink, green on black.     

Anatase—a pigment in ancient artwork or a modern usurper?

Fragments of wall-paintings from Roman villas in Easton Maudit, which date from ca 150 AD have been studied by Raman spectroscopy. An intact ancient Roman paint pot discovered in the remains of a villa in Castor, Cambridgeshire, still containing a mixture of white and red pigment was also analysed and the pigments identified as haematite and anatase. The discovery of anatase in the intact artist’s paint pot, particularly, and also on fragments of broken paint pots from the Easton Maudit villa site, is a unique contribution to current knowledge of ancient European pigment history, because the presence of this mineral has not hitherto been recognised fully in an ancient artist’s palette. The relative spectral response of anatase and haematite in the Raman data is compared with that of anatase and other red pigments such as minium, cinnabar, and litharge.     

Gold Gilding and Pigment Identification on a Post-Byzantine Icon from Kastoria,Northern Greece

The investigation of gilded gold, black and red pigments from the Byzantine icon of Panagia from the church of Agioi Anargyroi Gymnasiou in Kastoria, northern Greece is the aim of this study. Small fragments, having a gold leaf finish, were detached from the icon and were analyzed by Environmental Scanning Electron Microscopy coupled to Energy Dispersive System (ESEM-EDS) and Raman microscopy. The chemical (EDS) composition of the gilding material revealed a high gold content alloy (Au 81.34 wt%) with trace amounts of silver (Ag 1.66 wt%), copper (Cu 0.62 wt%) and iron (Fe 0.58 wt%). The Raman spectrum of the gold leaf showed characteristic bands at 236, 369, and 468 cm^?1. The red pigment on the surface comprises of Hg, S, and minor amounts of Pb and is attributed to the minerals cinnabar (HgS) and minium (Pb₃O₄). The black pigment has high carbon content, attributed to organic material (black carbon). The micro-Raman spectroscopy provided a more detailed determination of the composition of the red and black pigments. In particular, the vivid red color was attributed to cinnabar (bands at 253 and 342 cm^?1). Particles of black carbon (bands at 1345 and 1577 cm^?1) and oxalates (band at 861 cm^?1) were determined on the black pigments. Dark regions on the pigmented surface were assigned to a mixture of cinnabar [bands at 253 and 342 cm^?1] and minium [bands at 120, 142, 288, and 545 cm^?1]. The latter lead oxides might have been used either as a dryer or a burnish agent for the gold leaf. The micro-structural and chemical analysis of several distinct strata of the icon, as observed under ESEM, revealed a red-colored stratum beneath the gold leaf, with an iron aluminosilicate composition. This is the so-called bole (red clay) commonly used as sub-strata for gilding art objects. Multiple layers of white ground material, composed of gesso (gypsum) underlie the bole strata. Moreover, one thin organic binder (animal glue) was is observed within the gesso ground of the icon.     

Measurement of the δ34S value in methionine by double spike multi‐collector thermal ionization mass spectrometry using Carius tube digestion

Methionine is an essential amino acid and is the primary source of sulfur for humans. Using the double spike (³³S‐³⁶S) multi‐collector thermal ionization mass spectrometry (MC‐TIMS) technique, three sample bottles of a methionine material obtained from the Institute for Reference Materials and Measurements have been measured for δ³⁴S and sulfur concentration. The mean δ³⁴S value, relative to Vienna Canyon Diablo Troilite (VCDT), determined was 10.34 ± 0.11‰ (n = 9) with the uncertainty reported as expanded uncertainties (U). These δ³⁴S measurements include a correction for blank which has been previously ignored in studies of sulfur isotopic composition. The sulfur concentrations for the three bottles range from 56 to 88 µg/g. The isotope composition and concentration results demonstrate the high accuracy and precision of the DS‐MC‐TIMS technique for measuring sulfur in methionine. Published in 2010 by John Wiley & Sons, Ltd.     

Stable isotope variation as a tool to trace the authenticity of beef

Organic beef coming principally from Germany was analysed for the hydrogen, carbon, oxygen, nitrogen and sulfur stable isotopic composition to test the possibility of tracing back the geographical origin. Since there is a well-known pattern of D/H and ¹⁸O/¹⁶O in meteoric water and in ground water, there is an existing link to tissue water in the beef. By including the stable isotope ratios of the other elements of life further information is available: soils show different isotope ratios of ¹⁵N/¹⁴N and ³⁴S/³²S depending on the geological composition, cultivation and atmospheric sulfur deposition. As organic farming is mainly obliged to use only their produced fodder, that ratio is reflected in the beef as well.Different organic beef samples from various German farms have been collected and analysed over nearly two years. To check the differentiation of foreign beef, samples from Argentina and Chile were also included in the study. The analyses of meat samples indicate that it is possible to trace back the region (e.g. Argentina and Germany) by using isotopes of oxygen and hydrogen. A local geographical differentiation can be done by using the stable isotopes of nitrogen and sulfur, as was demonstrated for three farms in Colonia Bay. An optimal differentiation also depends on the quality of further information (e.g. the season, kind of cattle breeding or the declaration of the local geographical origin). Certainly authenticity of beef is not only linked with the geographical origin but can also reflect the differentiation of organic and conventional farming. The fodder of organic cattle farming consists mainly of C₃ plants and the use of C₄ plants is more usual in conventional cattle farming. A ¹³C/¹²C ratio above –20 appears as a limit for organic farming. Increased values have to be controlled based on their authenticity.     

Direct analysis of mercury in Traditional Chinese Medicines using thermolysis coupled with on-line atomic absorption spectrometry

The purpose of this study is to develop and apply a mercury analyzer system capable of quantitative analysis of mercury in Traditional Chinese Medicines (TCM) drugs in the concentrations range from ng g⁻¹ to mg g⁻¹. No sample pre-treatment was needed and this greatly simplifies the analytical procedure and minimizes potential sources of contamination. The precisions of analyzing solid mercury standard sample and real TCM materials were 2.1% and 2.5-8.2%, respectively; and the recovery based on the analysis of standard reference materials ranged from 95.2% to 105%. The performance of the method has been compared with inductively coupled plasma-mass spectrometry (ICP-MS) technique and excellent agreements were observed between the two methods. The method has been applied to the investigation of Hg content in several TCM drugs containing or not containing cinnabar. Mercury concentration in the same TCM products differs widely with different manufacturers, suggesting that external contamination and the Hg presence in raw herbal materials are the main sources of Hg. In addition, comparison of mercury thermal releasing profiles between TCM drug and cinnabar suggests that mercury conversion from cinnabar to biological matrices-bound Hg could occur because of the aid of other ingredients in the formulated drug.     

Sulfur trace determination in petroleum products by isotope dilution ICP-MS using direct injection by thermal vaporization (TV-ICP-IDMS)

An accurate, sensitive, and fast method for direct determination of total sulfur in petroleum products after thermal vaporization of an isotope-diluted sample was developed by using ICP-MS. ³⁴S-labelled dibenzothiophene spike was used for the isotope dilution step. The isotope-diluted sample was injected into a thermal vaporizer which was directly connected by a heated transfer line to the plasma torch. Sample transport was achieved by using a helium gas flow, and the isotope ratio ³⁴S/³²S was determined within seconds after injection. No other sample preparation other than the simple and fast isotope dilution step, which enables accurate and sensitive determination of sulfur at high sample throughputs, is necessary. Thus, this technique fits all needs for routine analyses. Validation of the TV-ICP-IDMS method was carried out by analyzing the certified gas oil reference materials BCR672 and BCR107. Comparison of results for noncertified low- and high-boiling samples, obtained from an ICP-IDMS microwave-assisted digestion method, also resulted in very good agreement. The low detection limit of 40 ng/g and the large dynamic range of TV-ICP-IDMS fulfill all necessities to allow analysis of sulfur in different petroleum products, e.g., even at the low concentration level of ‘sulfur-free’ gasoline.     

An extensive colour palette in Roman villas in Burgos,Northern Spain: a Raman spectroscopic analysis

Seventy-five specimens from thirty fragments of Roman villa wall-paintings from sites in Burgos Castilla y Leon, Spain, have been analysed by Raman spectroscopy. This is the first time that a Raman spectrocopic study of Roman wall-paintings from Spain has been reported. The extensive range of tonalities and colour compositions contrasts with the results found in other provinces of the Roman Empire, for example Romano-British villas. Calcite, aragonite, haematite, caput mortuum, cinnabar, limonite, goethite, cuprorivaite, lazurite, green earth, carbon and verdigris have been found as pigments. Some mineral mixtures with different tonalities have been made using different strategies to those more usually found. Of particular interest is the assignation of the Tarna mine for the origin of the cinnabar used for obtaining the red colour in some specimens analysed here. The wide range of colours, tonalities and minerals found in some of the sites studied in this work is suggestive of a high social status for the community.     

Revised δ34S reference values for IAEA sulfur isotope reference materials S‐2 and S‐3

Revised δ³⁴S reference values with associated expanded uncertainties (95% confidence interval (C.I.)) are presented for the sulfur isotope reference materials IAEA‐S‐2 (22.62 ± 0.16‰) and IAEA‐S‐3 (−32.49 ± 0.16‰). These revised values are determined using two relative‐difference measurement techniques, gas source isotope ratio mass spectrometry (GIRMS) and double‐spike multi‐collector thermal ionization mass spectrometry (MC‐TIMS). Gas analyses have traditionally been considered the most robust for relative isotopic difference measurements of sulfur. The double‐spike MC‐TIMS technique provides an independent method for value‐assignment validation and produces revised values that are both unbiased and more precise than previous value assignments. Unbiased δ³⁴S values are required to anchor the positive and negative end members of the sulfur delta (δ) scale because they are the basis for reporting both δ³⁴S values and the derived mass‐independent Δ³³S and Δ³⁶S values. Published in 2009 by John Wiley & Sons, Ltd.