Characterization of >oil on copper> paintings by energy dispersive X-ray fluorescence spectrometry

Energy dispersive X-ray fluorescence is a common analytical tool for layer thickness measurements in quality control processes in the coating industry, but there are scarce microanalytical applications in order to ascertain semi-quantitative or quantitative information of painted layers. >Oil on copper> painting becomes a suitable material to be analysed by means of X-ray fluorescence spectrometry, due to the metallic nature of substrate and the possibility of applying layered models as used in coating industry. The aim of this work is to study the suitability of a quantitative energy dispersive X-ray fluorescence methodology for the assessment of the areal distribution of pigments and the characterization of painting methods on such kind of pictorial artworks. The method was calibrated using standard reference materials: dried droplets of monoelemental standard solutions laid on a metallic plate of copper. As an example of application, we estimated pigment mass distribution of two >oil on copper> paintings from the sixteenth and eighteenth centuries. Pictorial layers have been complementarily analysed by X-ray diffraction. Apart of the supporting media made of copper or brass, we could identify two different superimposed layers: (a) a preparation layer mainly composed by white lead and (b) the pictorial layer of variable composition depending on the pigments used by the artist on small areas of the painting surface. The areal mass distribution of the different elements identified in the painting pigments (Ca, Cr, Mn, Fe, Zn, Cd, Hg and Pb) have been determined by elemental mapping of some parts of the artworks. © 2011 Springer-Verlag.A. Pitarch gratefully acknowledges the Spanish Ministry of Education for the grant within the program of Formation of Graduate Stuff-FPU (reference AP2006-4591)Peer Reviewe

Objetos de oro y epicampaniforme en la Cova del Gegant. Relaciones en la costa mediterránea de la Península Ibérica durante la Edad del Bronce

En este trabajo se analiza el estrato XXV de la Cova del Gegant (Sitges, Barcelona), adscrito a la Edad del Bronce, y se destaca la problemática cronológica de este período. En este yacimiento encontramos decoraciones epicampaniformes del "Grupo del Nordeste", tradicionalmente atribuidas a un Bronce Antiguo, un osario colectivo datado por C14 en el Bronce Medio, ornamentos en ámbar/resina de amplia cronología y dos piezas áureas, muy escasas en el nordeste de la Península Ibérica, que vinculamos con el episodio sepulcral. Las piezas arqueológicas y la serie de dataciones radiocarbónicas nos proporcionan datos importantes sobre las redes de intercambio y los desplazamientos a lo largo de la fachada mediterránea de la Península Ibérica durante la Edad de Bronce

Dispersive micro solid-phase extraction using multiwalled carbon nanotubes combined with portable total-reflection X-ray fluorescence spectrometry for the determination of trace amounts of Pb and Cd in water samples

In this paper the combination of dispersive micro solid-phase extraction (DMSPE), using multiwalled carbon nanotubes (MWCNTs) as solid sorbents, with total-reflection X-ray fluorescence spectrometry (TXRF) is proposed for preconcentration and determination of lead and cadmium ions in water samples. The proposed sample preparation is quite simple and economic. After the sorption processes of the metals on the MWCNTs, the aqueous sample is separated by centrifugation and the metal loaded MWCNTs are suspended using a small volume of an internal standard solution and analyzed directly by TXRF. Parameters affecting the extraction process (complexing agent, pH of the aqueous sample, amount of MWCNTs) and TXRF analysis (volume of the deposited suspension on the reflector, drying mode, and instrumental parameters) have been carefully evaluated to test the real capability of the developed methodology for the determination of Cd and Pb at trace levels. For both elements the linear range is observed up to 50 ng mL(-1). Under optimized conditions detection limits are 1.0 ng mL(-1) and 2.1 ng mL(-1) for Cd(II) and Pb(II) ions, respectively. Both of the examined elements can be determined with quantitative recoveries (ca. 100%) and with an adequate precision (RSD = 6.0% and 10.5% for Cd(II) and Pb(II), respectively). Our results give insight into the possibilities of the combination of DMSPE and TXRF for trace metal determination in different types of environmental waters (sea, river and waste water).This work was supported by the Spanish National Research Program (Project ref. CGL2010-22168-C03-01) and the Bilateral Agreement (Lifelong Learning Program/Erasmus) for the Academic year 2012 – 2013 between the University of Silesia (Poland) and the University of Girona (Spain). Karina Kocot is grateful for the financial support of the UPGOW project, cofinanced by the European Union within the European Social FundPeer Reviewe

Determination of cadmium at ultratrace levels in environmental water samples by means of total reflection X-ray spectrometry after dispersive liquid-liquid microextraction

Until now, the determination of Cd at trace levels in aqueous samples by TXRF has been restricted. When Mo-target X-ray tubes are used, low sensitivity and interferences with Cd L-lines used for quantification prevent trace analysis. Alternatively, when W-target X-ray tubes are used Cd excitation is limited. For this reason, a sample pretreatment is usually necessary to extract, isolate and concentrate Cd prior to TXRF analysis. In the present contribution, the feasibility of a dispersive liquid-liquid microextraction approach (DLLME) combined with TXRF for ultratrace Cd determination in different types of environmental waters is shown. Parameters affecting the extraction procedure and TXRF measurement conditions have been carefully evaluated to ensure the highest sensitivity for Cd determination. Using the best analytical conditions, it was found that the minimum cadmium content that could be detected in an aqueous solution was 0.04 μg L-1. This value is more than two orders of magnitude lower compared with the direct TXRF analysis of Cd in aqueous samples. The precision of the methodology was evaluated in terms of relative standard deviation (RSD) of six replicate analyses of a standard solution containing 3 μg L-1. The precision of the method was determined to be approximately 5% RSD. In order to test the suitability of the method when dealing with complex matrices as well as the influence of interfering ions, the determination of Cd in spiked water samples (sea water, estuarine water and river water) at the levels of 1 μg L-1 and 5 μg L-1 was undertaken and Cd added to the samples was quantitatively determined. Our results give insight into the possibilities of the combination of DLLME and TXRF for ultratrace Cd determination in different types of environmental waters. © 2013 The Royal Society of Chemistry.This work was supported by the Spanish National Research Progam (Project ref. CGL2010-22168-C03-01)Peer Reviewe

Adularia-sericite type wallrock alteration at the María Josefa gold mine: An example of low sulfidation epithermal ore deposit, within te volcanic Rodalquilar Caldera (SE, Spain)

The authors are indebted to Prof. A. Arribas Jr. and other anonymous reviewer, for the comments and suggestions on the manuscript.The mineralogy of wallrock alteration in Maria Josefa mine was investigated in order to establish the paragenetic mineral association and their origin in the framework of the gold-alunite Rodalquilar mining district (SE Spain). Microprobe analyses exhibit two types of adularia existing in the aureoles of the Maria Josefa vein system reflecting the evidence of both replacement and neoformation dunng the alteration process. Three paragenetic association have been recognized: quartz-adularia, quartz-adulana-sencite and quartz-sericite. X-ray diffraction analyses were performed in order to identify and quantify the existing minerals. The data obtained indicate the presence of minor amounts of kaolinite, goethite, hematites, calcite, gypsum and jarosite. Pynte was identified as the principal base metal-containing mineral. The mineral paragenetic assemblages found in wallrock alteration at the Maria Josefa mine present a good example of low sulfidation type of epithermai gold deposit located penpherally to the Rodalquilar caldera structure, contrasting with the high-sulfidation type existing in the core.The field work, carned out in 199 1, was sponsored by the Agreement for Cooperation in Science and Technology between the Bulgarian Academy of Sciences and the Consejo Superior de Investigaciones Científicas. Two of iie authors (MKanazirski, 1,Queralt) received financial support from European Community (Programme for Cooperation in Sciences and Technology with Central and Eastem Countries).Peer reviewe

Energy dispersive X-ray fluorescence analysis of ancient coins: The case of Greek silver drachmae from the Emporion site in Spain

Greek colonizers arrived at the Iberian Peninsula at the beginning of the sixth century B.C. and founded a small colony known as Emporion in north-east Spain. By the fifth century B.C., this colony became a small polis with a well-organized administrative structure. In this context, the necessity of coinage was a fact and the first coins were minted [1]. Some of these coins were characterized by using energy dispersive X-ray fluorescence equipment. The analytical study focused on the elemental characterization of the coins minted from the fourth century to the first century B.C. and their compositional evolution during this period. The investigation has pointed out a very high fineness of the alloys throughout the time, with an average silver content around 98.32%, and the feasibility of energy dispersive X-ray fluorescence as a screening tool for the characterization of the alloys. © 2010 Elsevier B.V. All rights reserved.Pitarch has been the recipient of a grant from the Spanish Ministry of Education (ref. AP2006-4591).Peer Reviewe

X-ray fluorescence for multi-elemental analysis of vegetation samples

Presently, the development of analytical methods to determine elemental composition of vegetation samples is of significance in many different fields. This chapter discusses the details and potentials of different X-ray fluorescence (XRF) configurations in the field of multi-elemental analysis of vegetation samples. Most commonly used sample treatment procedures are also described. The chapter includes some of the many interesting applications of XRF in environmental and agronomic studies dealing with the analysis of vegetation samples. Some of the main advantages of XRF in the field of vegetation sample analysis over other atomic spectroscopic techniques include the simplicity of sample preparation and the possibility to determine elements such as P, S, Cl, and Br which can be of significance in biological processes.Peer reviewe

Geology of the Southern Central Andes, Northwest Argentina: An introduction

Bajo el título genérico de "Geología de los Andes Centrales Meridionales: El Noroeste Argentino" se recopilan un conjunto de trabajos realizados en los últimos años en sectores del Noroeste Argentino. Las investigaciones realizadas se localizan en la región andina de la provincia de Salta y territorios adyacentes. Este volumen monográfico reúne trabajos que constituyen el esfuerzo conjunto de veinticinco autores de diferentes países,europeos y suramericanos,trabajando en proyectos de colaboración internacional.La iniciativa de recopilar trabajos geológicos realizados recientemente en la zona surgió como una consecuencia del desarrollo del proyecto de investigación de la Comunidad Económica Europea "Study of Volcanic collapse calderas developed in transcurrent fault and their associated mineral deposits (Au, Ag, Sb, Pb, Zn and borates). Central Andes. Argentina" (CEE-CLI-CT92-0098).Peer reviewe

Mineralogía y elementos de los sedimentos actuales del río Llobregat (Barcelona)

[ES] El objetivo del presente trabajo es la adquisición de conocimientos previos acerca de la evolución mineralógica y de la distribución de elementos pesados en los sedimentos actuales del rio Llobregat (Barcelona, España). El análisis mineralógico se ha realizado por difracción de rayos X. Las concentraciones de Ba, Pb, Cr, Cu, Ni, Rb, Sr y Zn han sido determinadas por medio de espectrometria de fluorescencia de rayos X. Los resultados obtenidos permiten apreciar un marcado aumento del contenido en elementos pesados hacia el curso bajo el rio atribuible al mayor grado de contaminación. Pb y Cu presentan una notable relación en su comportamiento geoquirnico mientras que otros elementos contaminantes como Zn y Cr, con notable aumento en la desembocadura del rio, siguen una distinta dinámica de reparto.[EN] The object of the present work is to build on our existing knowledge of the mineralogical evolution and the distribution of heavy metals in the sediments presently existing in the river Llobregat (Barcelona, Spain). The mineralogical analysis was carried out by means of X-ray diffraction. The levels of concentration of Ba, Pb, Cr, Cu, Ni, Rb, Sr and Zn have been determined by means of X-ray fluorescence spectrometry. The results obtained enable us to observe a marked increase of the heavy meta1 content towards the lower course of the river, which may be attributed to the greater contamination level. Pb and Cu demonstrate a notable ~losenessin their geochemical behaviour whilst other contaminants such as Zn and Cr follow a different pattern of deposition, including a noticeable increase in concentration in the mouth of the river.Peer reviewe

Lixiviación de metales de sedimentos mineros hacia el medio hídrico en el distrito minero de Cartagena-La Unión (Murcia)

En este estudio se ha analizado el contenido en Cr, Cu, As, Zn y Pb de un sondeo de sedimentos de una rambla minera de la zona de Cartagena-La Unión (Murcia) mediante espectrometría de fluorescencia de rayos X. Asimismo se ha evaluado la lixiviación potencial de metales de estos residuos hacia el medio hídrico utilizando el test normalizado DIN 38414-S4 y la mineralogía en las diferentes muestras por difracción de rayos X. Los contenidos observados en los sedimentos sobrepasan los niveles establecidos por la legislación para ser considerados suelos contaminados para todos los metales estudiados excepto para Cr. También se ha observado que la lixiviación de metales es muy elevada para todos los metales obtenidos, superando hasta en 100 veces los valores establecidos para aguas potables. A pesar de ello, el porcentaje de lixiviación de metales respecto al contenido total es pequeño (1-2% como máximo), excepto para Zn, elemento que puede llegar hasta niveles del 60 %. Otro aspecto a considerar es la influencia de la mineralogía sobre la lixiviación de los metales, con un énfasis especial en el caso del Pb.In this study was evaluated the content of Cr, Cu, As, Zn and Pb in a sediment core at the Cartagena-La Unión mining district (Murcia Province) by means of X-ray fluorescence spectrometry. Additionally, the potential metals’ leaching to the hydrologic media was evaluated both through the use of the DIN 38414-S4 test and the mineralogy determined by means of X-ray diffraction. The observed heavy metal contents of the sediments overpass the levels established by the Spanish regulations to be considered as polluted soils for all the metals studied except Cr. Lixiviation tests exhibit a very high metal content reaching up to two orders of magnitude higher than the established values for drinking waters. Regarding to leaching percentages, they are low respect to the total heavy metal content (1-2%) except for Zn where the leaching content arrives to 60% in some levels. Mineralogy is especially noticeable for the case of Pb mobility.Este estudio ha sido realizado dentro del marco de los proyectos CGL2004-05963-C04 y CGL2007-66861- C04 del Plan Nacional de I+D+i del Ministerio de Educación y Ciencia. O. González-Fernández agradece también la beca BES2005-6810 del programa de Formación de Personal Investigador del Ministerio de Educación y Ciencia.Peer reviewe