Hand-held Energy Dispersive X-ray Fluorescence Research Articles

In-Field Obsidian XRF Analysis of Sites in the Lion Mountain Area and Gallinas Mountains of West-Central New Mexico

ABSTRACT The Gallinas Mountains of west-central New Mexico were home to agriculturalists between ca. a.d. 850 and 1450. Ongoing research of the Lion Mountain Archaeology Project (LMAP) has allowed for in-field analysis of surface obsidian artifacts via portable handheld energy dispersive X-ray fluorescence spectrometry (ED-XRF). Influenced by principles of preservation archaeology and the archaeological repository curation crisis, the LMAP has sought to design and conduct field research to gather the most data with the least amount of impact to sites. Non-destructive in-field analysis via portable handheld ED-XRF subscribes to these goals while also providing answers to significant questions about human behavior. Results show that variable patterns of obsidian source utilization and procurement strategies existed both through time and between contemporaneous populations. These results are indicative of a shifting system of exchange and social interaction between residents of the region and surrounding areas during the Ancestral Pueblo occupation of the area.

Long-term in situ non-invasive spectroscopic monitoring of weathering processes in open-air prehistoric rock art sites.

In this work, an innovative non-destructive monitoring methodology based on the analysis over time of open-air rock art sites is presented. This approach is based on the combination of in situ spectroscopic and chemometric studies to diagnose and monitor the state of conservation of rock art sites. Data acquired over a period of time by non-invasive analytical techniques such as portable Raman spectrometry (RS) and handheld energy-dispersive X-ray fluorescence (HH-EDXRF) spectrometry are compared to detect physicochemical changes that could affect the rock painting integrity. To demonstrate the applicability of the proposed procedure, three analysis campaigns (between 2013 and 2016) were carried out, analyzing Levantine rock pictographs preserved in the rock shelter of Solana de las Covachas VI (Albacete, Spain; see Electronic Supplementary Material (ESM) Fig. S1). The analyzed areas showed different types of active weathering processes such as gypsum and calcium oxalate formation, giving rise to conservation issues such as painting fading, surface loss, microbial colonizations, and formation of crusts. Results evidence that the proposed methodology can be very useful to monitor chemical changes in the surface of the walls where the rock art is located, thus obtaining crucial information for its preservation and management.

A Paleocene vertebrate-bitten crocodilian coprolite from Liverpool Point, Maryland, U.S.A.

Although still exceedingly rare, the number of known vertebrate-bitten coprolites continues to increase. A vertebrate-bitten coprolite is herein reported from the Piscataway Member of the upper Paleocene Aquia Formation at Liverpool Point, Maryland, U.S.A.The specimen is described, figured, and chemically characterized by means of non-destructive hand-held energy dispersive X-ray fluorescence (HH-XRF). Four roughly parallel and evenly spaced gouges disrupt the surface of this compound ichnofossil. Many more much smaller markings, interpreted as feeding traces by smaller organisms (invertebrates or small actinopterygian fishes?), also ornament its surface. Whereas the studied coprolite can be identified most likely as the fossilized feces of a crocodilian, the identity of the vertebrate(s) that bit it remains unknown.

Mercury Exposure Associated with Use of Skin Lightening Products in Jamaica.

Background.Skin bleaching is a major health concern among Jamaicans. A common ingredient in skin lightening products is mercury. Mercury is a toxic substance that can cause damage to the gastrointestinal tract, nervous system and kidneys.Objective.The objectives of this study were to use different analytical techniques to measure mercury concentrations in popular skin lightening products used in Jamaica and to assess individual levels of mercury exposure based on product usage.Methods.Sixty skin lightening products were purchased from different vendors across various locations in Jamaica. Each product was initially screened for mercury using a portable handheld energy dispersive X-ray fluorescence (XRF) analyzer. In addition, 25 out of 60 products were further measured using cold vapor atomic absorption spectroscopy (CVAAS). Questionnaires were distributed to users of skin lightening products to determine their usage patterns.Results.Six products had mercury concentrations above the United States Food and Drug Administration (FDA) allowable limit of 1 ppm, of which three products contained alarmingly high concentrations (i.e. > 400 ppm). The majority of products (57 out of 60) had mercury concentrations below 10 ppm. The mercury concentrations in skin lightening products ranged from 0.05 ppm to 17,547 ppm. In our sample, 51% of women and 49% of men used skin products more than once per day.Conclusions.On average, creams contained more mercury than lotions and soaps. Individuals who use skin lightening products in Jamaica may be at risk for high mercury exposure, as some popular products were found to have mercury concentrations above the allowable limit.Competing Interests.The authors declare no competing financial interests.

Developing a quantitative mudrock calibration for a handheld energy dispersive X-ray fluorescence spectrometer

Handheld energy dispersive X-ray fluorescence (hhEDXRF) spectrometers enable rapid and non-destructive means of quantifying the elemental composition of rocks. Advances in hhEDXRF technology have resulted in their widespread usage in the geological sciences. Currently, most popular hhEDXRFs lack lithology-specific calibrations and in turn acquire datasets with high precision but in many cases with unknown or low accuracy. This study derives a methodology to create an internal regression-based mudrock calibration for a hhEDXRF analyzer, with the aim of increasing the analytical quality of elemental data collected from core and outcrop samples. For this study we utilize 64 compositionally diverse Middle Devonian mudrock samples from four cored locations within the central Appalachian basin. Samples were analyzed on both a hhEDXRF and a quantitatively superior bench-top wavelength-dispersive XRF (WDXRF) spectrometer. Utilizing linear regressions, hhEDXRF values were calibrated to the values of the WDXRF for individual elements. Measurements from the two XRF modes record the following coefficients of determination: Zn, Mo, and Ca (r2 > 0.99), Al, K, Ti, Fe, Ni, V, Cu, and Pb (r2 > 0.92), Zr and Si (r2 > 0.78), and Cr (r2 = 0.56). To assess precision, relative standard deviations (RSD) were calculated for each element based on repeated measurements collected on internal reference samples. All elements recorded RSD values of <8.8%, excluding Cr, which recorded values of 14–25%. Magnesium (Mg), Cl, and Ag were below the limit of detection by the hhEDXRF and thus RSD values could not be computed. To assess hhEDXRF accuracy, we propose a novel “iterative blind test” approach, which quantifies accuracy through deriving the percentage difference between the calibrated hhEDXRF value, derived from the blind test, and WDXRF values for each element. Si, Ti, Al, Fe, Ni, Cu, Zn, and Zr record percentage difference values of <10%. For Mn, Ca, Cr, V, Mo and Pb, a minority of samples (<13% on average) record concentrations below their reliable detection limit (RDL). Excluding measurements below the RDL, the elements record percent difference values between 6 and 15%. Potassium yielded measurements outside of the RDL and was the only element that returned percentage difference values of >20%, outside of the acceptable limit. The internal mudrock calibration creates high analytical quality datasets for more robust analyses when compared to previous approaches.

Benchtop and Handheld Energy-Dispersive X-Ray Fluorescence (EDXRF) as Alternative for Selenium Concentration Measurement in Biofortified Broccoli Seedling

Biofortification of crops with selenium (Se) is an effective strategy to increase the consumption of this micronutrient. Inductively coupled plasma mass spectrometry (ICP-MS) is one of the most used techniques in quantifying Se. However, due to some disadvantages (high cost, long analysis time, and being destructive), there is a need for new alternatives to Se quantification. This study aimed at establishing instrumental parameters for Se quantification, using two energy-dispersive X-ray fluorescence spectrometry (EDXRF) techniques (benchtop and handheld) in Se-biofortified broccoli seedlings and comparing it with ICP-MS. The results showed that the selection of proper filters for both EDXRF systems was crucial for determining Se and, when compared with ICP-MS, presented similar results for selenium-biofortified broccoli seedling treatments (BS50Se). In addition, the EDXRF techniques presented a Se limit of detection (LOD) at 0.6–0.9 mg kg−1. This study demonstrates that EDXRF systems were successfully applied to concentration measurement of Se in biofortified samples and linked to low cost and shorter analysis time.

In situ non-invasive multianalytical methodology to characterize mosaic tesserae from the House of Gilded Cupids, Pompeii

Mosaics, one of the most important decorative artworks in the Roman culture, were usually elaborated with a set of tesserae joined with lime or others binders to form geometric or figurative decorations. The identification of both substrate and colored compounds of the tesserae is a challenge for chemists and archaeologists. In this work, two mosaics present in the House of Gilded Cupids from the Archaeological Park of Pompeii were analyzed in situ by non destructive techniques. Raman and Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopies were used for the molecular and mineralogical characterization, and hand-held energy dispersive X-ray fluorescence (HH-EDXRF) spectrometry and Laser Induced Breakdown Spectroscopy (LIBS) for the elemental analysis. LIBS in-depth analysis was performed to obtain insights about the thickness of the pictorial layer determining that the thickness of red and orange pictorial layers was higher than 140 μm. The results showed that white tesserae were mainly composed by calcite, while local black colored volcanic rocks were used to manufacture black tesserae. Red and orange tesserae were composed by a calcite-based matrix with a hematite pictorial layer applied over it. Orange color was obtained by diluting hematite in the calcite matrix. Principal component analysis (PCA) of the XRF data was performed to observe differences and/or similarities between the analyzed mosaics; the samples projection of the PCA showed clear groupings.

In-situ analytical study of bricks exposed to marine environment using hand-held X-ray fluorescence spectrometry and related laboratory techniques

In this work, the degradation processes that take place in bricks exposed to marine environments have been studied. Taking into account the importance of this building material where the silicates present in the final product act as stabilizer in the porous material itself, it is necessary to understand the decay processes that occur in these aggressive environments. As is known, the marine aerosol carries different types of salts, such as chlorides, sulfates, nitrates, etc., present in surrounding environment exerting a negative influence on the materials producing cracking and disintegration processes of the material and consequently loss of brick wall stability. Nowadays the development of portable devices is taking much more importance helping researchers to resolve problems in the field in a fast and easy way. In order to extract fast and satisfactory results about the conservation state of different bricks from Punta Begoña Galleries (Getxo, Basque Country, Spain), an in-situ analytical methodology was developed based on the use of hand-held Energy Dispersive X-ray fluorescence spectrometry (HH-ED-XRF) assisted with other laboratory techniques (μ-ED-XRF and X-Ray Diffraction) in order to corroborate and complement the information obtained in-situ. This construction undergoes the influence of marine aerosol, industrial port, power generation plants, and a fuel refinery among others. The pathologies visually observable in these bricks are disintegration, breakup and detachment of the bricks. The presence of deterioration compounds in the bricks has been studied according to the orientations of the bricks inside the construction.

Red and blue colours on 18th–19th century Japanese woodblock prints: In situ analyses by spectrofluorimetry and complementary non-invasive spectroscopic methods

The study of fragile artworks kept in museums requires mobile devices, short time of analysis and minimal disturbance to insure their good preservation. In situ reflectance spectroscopy and spectrofluorimetric studies are mostly developed for pigment characterization. A recently-designed μspectrofluorimeter (LED μSF) dedicated to in situ measurements, that uses UV-light emission diodes (LED) as excitation sources, was used to verify its potentiality for the identification of pigments and dyes. The colours of five Japanese woodblock prints from the Museum of Zaragoza (Spain) were studied by the combination of UV-VIS-IR spectroscopies and hand-held energy dispersive X-ray fluorescence spectrometer (HHED-XRF), together with Raman Spectroscopy. This study focused on the analysis of red and blue colours in prints by Koryūsai, Utamaro and Eisen (18th–19th centuries). The interpretation of the in situ fluorescence emission spectra could be rather difficult because of the variety of pigment mixtures, natural ageing of colorants and fluorescence of the support (paper), that could lead to spectral changes or band shifts. The combination with diffuse reflectance spectroscopy (DRS), hyperspectral imaging techniques (HSI), and HHED-XRF completed the interpretation of these results. A specific database was built analyzing reference samples made in accordance with Japanese printings techniques and materials. Inorganic and organic red (vermilion, red lead, cochineal, red safflower) and blue (Prussian blue, indigo, dayflower) pigments were used alone or as a mixture to modify the hues. The identification of Prussian blue could be a clue about the relations existing between East and West and, its presence sometimes questioned the dating of some early printings.

In situ non-invasive characterization of the composition of Pompeian pigments preserved in their original bowls

Pigments are one of the most important archaeological records recovered from the burial of Pompeii. Therefore, their analysis and characterization is an important task from the historical, archaeological and chemical point of view. In this work, a unique collection of various coloured raw pigments conserved in their original bowls recovered from the archaeological excavations of Pompeii was characterized. Nowadays, these pigments are stored both in the Naples National Archaeological Museum (MANN) and in the Applied Research Laboratory from the archaeological site of Pompeii (ARLP) due to its high archaeological value. For the molecular analysis, in situ micro-Raman spectroscopy was used and the elemental characterization was conducted by means of hand-held energy dispersive X-ray fluorescence (HH-ED-XRF). Mercury sulphide (HgS) and red ochre (hematite, Fe2O3) were identified in different red pigments and yellow ochre (goethite, FeOOH) in the analyzed yellow colours. The analyzed blue pigments were Pompeian blue (CaCuSi4O10) in all cases, green pigments were composed mainly by malachite (Cu2CO3(OH)2) and the white one resulted to be dolomite CaMg(CO3)2. Pink powders appeared to be lake pigments, using madder lake (alizarin and purpurin) as organic colorant in order to dye the inorganic mordant (local clays). In the case of blue and pink pigments Principal Component Analysis (PCA) was performed in order to see similarities/differences in the elemental composition among samples of the same colour. Groups within samples of the same colour were identified pointing out different sources of the raw material or enrichments in leachable metals present in soils during the burial.

Trentepohlia algae biofilms as bioindicator of atmospheric metal pollution

In this work, a reddish biocolonization composed mainly by Trentepohlia algae affecting a synthetic building material from a modern building from the 90s located in the Bizkaia Science and Technology Park (Zamudio, North of Spain) was characterized and its ability to accumulate metals coming from the surrounding atmosphere was evaluated. To asses if these biofilms can act as bioindicators of the surrounding metal pollution, a fast non-invasive in situ methodology based on the use of hand-held energy dispersive X-ray fluorescence (HH-ED-XRF) was used. In order to corroborate the in situ obtained conclusions, some fragments from the affected material were taken to analyze the metal distribution by means of micro-energy dispersive X-ray fluorescence spectroscopy (μ-ED-XRF) and to confirm the presence of metal particles deposited on it using Scanning Electron Microscopy coupled to an Energy Dispersive Spectrometer (SEM-EDS). In order to confirm if Trentepohlia algae biofilms growing on the surface of building materials could be a fast way to in situ provide information about the surrounding metal pollution, a second Trentepohlia algae biofilm growing on a different kind of material (sandstone) was analyzed from an older historical building, La Galea Fortress (Getxo, North of Spain).

Combination of in situ spectroscopy and chemometric techniques to discriminate different types of Roman bricks and the influence of microclimate environment.

Red and yellow bricks are the wall-building materials generally used in Roman masonries. The reasons for the different coloration are not always understood, causing loss of crucial information both for the conservation and for the archaeological knowledge of the cultural sites. In this work, a combination of in situ analyses, employing portable Raman spectroscopy and handheld energy dispersive X-ray fluorescence (HH-ED-XRF) spectroscopy along with chemometric analysis, was carried out on ancient Roman bricks of the "Casa di Diana" building (Ostia Antica, Italy-130 CE). Specifically, the compounds and the characteristic elements, which describe each type of brick (red and yellow), were studied avoiding destructive or invasive sampling. The molecular analysis allowed us to identify the major and minor compounds that characterise the bricks (anatase, hematite, quartz, calcite and silicates). However, the elemental analysis gave more useful information. Thus, the complex HH-ED-XRF data matrix generated was treated by a specific principal component analysis (PCA) to identify behavioural differences of the coloured bricks. The results revealed that Ca and Fe are the discriminatory elements for the two types of bricks. The PCA outcomes suggest that the contribution of certain elements is different in the bricks (mainly Ca, P, Sr, As and S, for yellow bricks), which could indicate different raw materials. Even among bricks with the same red colour (Al, Si, Ti, K, Fe, Cr, Mn, Ni, Zn, Cu, Rb and Zr, seemed to be the elements linked to raw materials), as a function of the surface impacts (orientation and microclimate affect the salts' formation), a distinction was made. Furthermore, the PCA pointed out that the yellow bricks are those more affected by decaying processes (related with Ca, P and S), complying with the Raman spectroscopy results in which the efflorescences (gypsum) affect especially the surface of these types of bricks.

A non-invasive in situ methodology to characterise the lacquers and metals from the Edo period Japanese armour

Japanese armour is thought to have evolved from the armour used in ancient China and Korea. Few are the works dealing with the characterisation of the materials used to create this appreciate artworks and most of them are focused on the characterisation of the helmet. In this work we present for the first time an in situ non-invasive methodology to characterise the composition of both metals/alloys and lacquers used to create a Japanese armour from the Edo period (1603–1869) property of the Armoury Museum of Alava (Basque Country, Spain). The armour was in situ investigated, without the necessity of taking any sample, for its later conservation in the Restoration Service from the Provincial Council of Alava (Basque Country, Spain). Firstly, by means of the use of a hand-held energy dispersive X-ray fluorescence spectrometer (HH-ED-XRF), the elemental composition of the metals/alloys of the armour was evaluated. This analysis determined that the kabuto (helmet) and the dō (cuirass) were made of at least seven different materials including their main body and decorations. Apart from the elemental characterisation and by using a portable Fourier Transform infrared spectrometer, which implements a Diffuse Reflectance sampling interface (DRIFT), the nature of the lacquer used in the armour was also determined (urushi). Thanks to the penetrating analysis that can be achieved using the HH-ED-XRF the nature of the substrate used to lacquer the armour was also approached. Moreover, portable Raman spectroscopy also assisted DRIFT results in the identification of later interventions (nitrocellulose) done in the lacquered areas avoiding any sampling process and further analysis in the laboratory.

In situ X-ray fluorescence-based method to differentiate among red ochre pigments and yellow ochre pigments thermally transformed to red pigments of wall paintings from Pompeii.

Most of the magnificent wall paintings from the ancient city of Pompeii are decorated with red and yellow colors coming from the ochre pigments used. The thermal impact of the pyroclastic flow from the eruption of Vesuvius, in AD 79, promoted the transformation of some yellow painted areas to red. In this work, original red ochre, original yellow ochre, and transformed yellow ochre (nowadays showing a red color) of wall paintings from Pompeian houses (House of Marcus Lucretius and House of Gilded Cupids) were analyzed by means of a handheld energy-dispersive X-ray fluorescence spectrometer to develop a fast method that allows chemical differentiation of the original red ochre and the transformed yellow ochre. Principal component analysis of the multivariate obtained data showed that arsenic is the tracer element to distinguish between both red colored ochres. Moreover, Pompeian raw red and yellow ochre pigments recovered from the burial were analyzed in the laboratory with use of a benchtop energy-dispersive X-ray fluorescence spectrometer to confirm the elemental composition and the conclusions drawn from the in situ analysis according to the yellow ochre pigment transformation in real Pompeian wall paintings.

In situ Determination of K, Ca, S and Si in Fresh Sugar Cane Leaves by Handheld Energy Dispersive X-Ray Fluorescence Spectrometry

A portable energy dispersive X-ray fluorescence spectrometer was evaluated in the in situ analysis of fresh sugar cane leaves for real time plant nutrition diagnosis. Fresh leaf fragments (n = 10 sugar cane varieties; 20 fragments per leaf; 2 measurement sites per fragment) were irradiated and the averaged data from X-ray characteristic emission lines intensities (for K, Ca, S and Si Kα lines) were in close agreement with mass fraction data obtained by a validated comparative method. The linear correlation coefficients (r) ranged from 0.9575 for Ca to 0.9851 for Si. The obtained limits of detection were at least two-fold lower than the critical nutrient levels. Manganese can also be properly determined, but validation still requires more robust calibration models. The proposed method is a straightforward approach towards the fast evaluation of the nutritional profile of plants avoiding time-consuming steps, which involve drying, grinding, weighing, and acid digestion.

Study of corrosion in archaeological gilded irons by Raman imaging and a coupled scanning electron microscope-Raman system.

In this work, analytical and chemical imaging tools have been applied to the study of a gilded spur found in the medieval necropolis of Erenozar (Bizkaia, Spain). As a first step, a lot of portable equipment has been used to study the object in a non-invasive way. The hand-held energy-dispersive X-ray fluorescence equipment allowed us to characterize the artefact as a rare example of an iron matrix item decorated by means of a fire gilding technique. On the other hand, the use of a portable Raman system helped us to detect the main degradation compounds affecting the spur. Afterwards, further information was acquired in the laboratory by analysing detached fragments. The molecular images obtained using confocal Raman microscopy permitted us to characterize the stratigraphic succession of iron corrosions. Furthermore, the combined use of this technique with a scanning electron microscope (SEM) was achieved owing to the use of a structural and chemical analyser interface. In this way, the molecular characterization, enhanced by the magnification feature of the SEM, allowed us to identify several micrometric degradation compounds. Finally, the effectiveness of one of the most used desalination baths (NaOH) was evaluated by comparing its effects with those provided by a reference bath (MilliQ). The comparison proved that basic treatment avoided any side effects on the spur decorated by fire gilding, compensating for the lack of bibliographic documentation in this field.This article is part of the themed issue 'Raman spectroscopy in art and archaeology'.

Characterization of Roman glass tesserae from the Coriglia excavation site (Italy) via energy-dispersive X-ray fluorescence spectrometry and Raman spectroscopy

The combined use of handheld energy-dispersive X-ray fluorescence spectrometry, Raman spectroscopy, and micro-energy-dispersive X-ray fluorescence spectrometry permitted the characterization of Roman glass tesserae excavation from the Coriglia (Italy) archeological site. Analyses of ten different glass colors were conducted as spot analyses on intact samples and as both spot analyses and line scans on select cross-sectioned samples. The elemental and molecular information gained from these spectral measurements allowed for the qualitative chemical characterization of the bulk glass, decolorants, opacifiers, and coloring agents. The use of an antimony opacifier in many of the samples supports the late Imperial phasing as determined through numismatic, fresco, ceramics, and architectural evidence. And dealinization of the exterior glass layers caused by the burial environment was confirmed.

Assessment of marine and urban-industrial environments influence on built heritage sandstone using X-ray fluorescence spectroscopy and complementary techniques

The sandstone used in the construction of the tower of La Galea Fortress (Getxo, north of Spain) shows a very bad conservation state and a high percentage of sandstone has been lost. The fortress is located just on a cliff and close to the sea, and it experiments the direct influence of marine aerosol and also the impact of acid gases (SOx and NOx) coming from the surrounding industry and maritime traffic. This environment seems to be very harmful for the preservation of the sandstone used in it, promoting different pathologies (disintegration, alveolization, cracking or erosion blistering, salts crystallization on the pores, efflorescences etc.). In this work, a multianalytical methodology based on a preliminary in-situ screening of the affected sandstone using a handheld energy dispersive X-ray fluorescence spectrometer (HH-ED-XRF) and a subsequent characterization of extracted sample in the laboratory using elemental (μ-ED-XRF, Scanning Electron Microscope coupled to an X-Max Energy-Dispersive (SEM-EDS) and Inductively coupled plasma mass spectrometry (ICP-MS)) and molecular techniques (micro-Raman spectroscopy (μ-RS) and X-ray Diffraction (XRD)) was applied in order to characterize the original composition of this kind of stone and related deterioration products. With the whole methodology, it was possible to assess that the sandstone contain a notable percentage of calcite. The sulfation and nitration of this carbonate detected in the stone led to the dissolution process of the sandstone, promoting the observed material loss. Additionally, the presence of salts related with the influence of marine aerosol confirms that this kind of environment have influence on the conservation state of the sandstone building.

Multispectroscopic and Isotopic Ratio Analysis To Characterize the Inorganic Binder Used on Pompeian Pink and Purple Lake Pigments.

Because of the fact that pigments are not ubiquitous in the archeological record, the application of noninvasive analytical methods is a necessity. In this work, pink and purple lake pigments recovered from the excavations of the ancient city of Pompeii (Campania, Italy) and preserved in their original bowls at the Naples National Archaeological Museum (Italy) were analyzed to characterize the composition of their inorganic binders (mordants). In situ preliminary analyses using a hand-held energy dispersive X-ray fluorescence spectrometer (HH-ED-XRF) allowed us to determine the use of an aluminosilicate enriched in Cu and Pb. Scanning electron microscopy coupled to energy dispersive X-ray spectrometry (SEM-EDS) and benchtop ED-XRF analyses confirmed these results, while inductively coupled plasma mass spectrometry (ICPMS) allowed one to determine the concentration of major, minor, and trace elements. The use of other techniques such as X-ray diffraction (XRD), and micro-Raman and infrared spectroscopies allowed one to characterize the pigments at the molecular level. The high concentration of Cu detected in the pigments (1228-12937 μg g(-1)) could be related to the addition of Cu salts to obtain the desired final hue. The concentrations of Pb (987-2083 μg g(-1)) was also remarkable. Lead isotopic ratio analysis ((206)Pb/(207)Pb) suggested a possible origin related to the leaching of the ancient lead pipes from Pompeii and the subsequent transfer to the buried pigments or to the inorganic binder. Molecular analysis also showed that the binder is composed of an allophane-like clay. Moreover, it was possible to determine that to obtain the final purple hue of a specific pigment, Pompeian blue pigment was also mixed into the dyed clay.

In-situ multianalytical methodology to evaluate the conservation state of the entrance arch of La Galea Fortress (Getxo, north of Spain)

An innovative in-situ multianalytical methodology is presented to assess the conservation state of a sandstone entrance arch of 18th century La Galea Fortress, located in Getxo, north of Spain. The high number of areas to analyze conducted us to select several portable instruments to perform the work in-situ, that taken measurements in more than 250 points of the arch. The first screening was performed by means of Infrared Thermography (IRT) allowing us to observe the areas with high moisture and loss of material. Then a careful in-situ spectroscopic analysis was conducted using two portable instruments, a hand-held energy dispersive X-ray Fluorescence spectrometer (HH-ED-XRF) and a portable Raman spectrometer that use a 785nm laser as the excitation source. To validate the in-situ analyses, few micro-samples were taken to perform laboratory analyses using Scanning Electron Microscopy coupled to Energy Dispersive X-ray Spectrometer (SEM-EDS). All the information was appropriate to characterize the different chemical pathologies that the entrance arch is suffering. The usefulness of the selected portable devices as analytical tools for field analyses, to detect key molecular compounds (mineral phases that cannot be considered as belonging to the original materials in the arch) that explain the decaying pathways caused by the interaction of atmospheric stressors and ions in the rain/infiltration waters with the compounds in the stones and mortars, was corroborated.