X-RAY SPECTROMETRY X-Ray Spectrom. 2008; 37: 399–409 Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/xrs.1088 The use of a portable energy dispersive x-ray fluorescence spectrometer for the characterization of patinas from the architectural heritage of the Iberian peninsula Carmen Vazquez-Calvo, 1* Blanca G ´ omez Tub´ ıo, 2 Monica Alvarez de Buergo, 1 In ´ es Ortega Feliu, 3 Rafael Fort 1 and Miguel Angel Respaldiza 3 1 Instituto de Geolog´ ıa Econ ´ omica (CSIC-UCM), Departamento de Petrolog´ ıa y Geoqu´ ımica 2 Universidad de Sevilla, Departamento de F´ ısica Aplicada III, E.S.I 3 Centro Nacional de Aceleradores (CSIC) Received 25 January 2008; Revised 28 March 2008; Accepted 6 May 2008 This article focuses on the study of patinas by means of a non-destructive and fast energy dispersive x-ray fluorescence (EDXRF) technique using portable equipment. The term patina is referred here to thin films or coverings (5 – 500 μm thick) on the surface of stone building materials, characterized by a common yellowish colour and a common presence of calcium carbonate, calcium sulphate, calcium oxalate, calcium phosphate, silicate and iron oxide and/or hydroxide. Some of these patinas are the result of applied past treatments with protective and/or aesthetical purposes. The main aim of this article is to assess the potential of the technique, together with the determination of the elemental composition of the samples and the provision of analytical information leading to the discrimination between different types of patinas. This work proved that the EDXRF spectrometry is a useful technique for qualitative and even semi-quantitative analyses of patinas in situ. It is a reliable method for a first approach to the study of a patina of any building. The results obtained showed that the patina is characterized by the presence and enrichment of elements like Si, P, K, Fe, Ti and Mn. For this reason, they could be considered as characteristics of this kind of material. Copyright  2008 John Wiley & Sons, Ltd. INTRODUCTION This article focuses on the study of patinas by means of a non- destructive and fast energy dispersive x-ray fluorescence (EDXRF) technique using portable equipment. The term patina is an ambiguous term (actually it is polysemous), as it can be used, for instance, for referring films on metals or, as here, to refer to thin films or coverings on the surface of stone building materials. These films are characterized by a common yellowish colour and a common presence of some of the following minerals: calcium carbonate, calcium sulphate, calcium oxalate, calcium phosphate, silicate (quartz, feldspar, etc.), clay minerals and iron oxide and/or hydroxide. 1–9 The thickness of these films is heterogeneous, ranging from 5 – 10 to 500 μm approximately. They have been studied mainly by classical techniques as x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy or scanning electron microscopy with coupled energy dispersive spectrometer (SEM-EDS), 10 among others. Some of them are the result of applied past treatments with protective and/or aesthetical purposes. 1,11 The main aim of this article is to assess the potential of the technique, used in other cultural heritage studies, due to the L Correspondence to: Carmen Vazquez-Calvo, Instituto de Geolog´ ıa Econ´ omica (CSIC-UCM), Departamento de Petrolog´ ıa y Geoqu´ ımica. E-mail: carmenvazquez@geo.ucm.es advantage of non-destructive, sensitive and multi-elemental method and it allows the ‘in situ’ analysis in its portable version. 12 – 14 Other considered aims are those regarding the determination of the elemental composition of the samples and also to provide analytical information leading to the discrimination between different types of patinas. Some of these samples were analysed in the previous studies 1,6,7,9 using other techniques including optical microscopy, SEM and electron microprobe. Table 1 shows the list of samples and the building (name, locality and region) from where they were collected. Figure 1 shows the map of Spain and Portugal where the localities, where sampling was carried out, are marked. It is necessary to consider the kind of substrate on which the patinas are found because this might condition the results obtained by means of EDXRF spectrometry. In most of the samples the substrate is limestone; in some others it is dolostone (samples from Cifuentes), sandstone with calcareous cement (samples from Aranda de Duero and Pe ˜ naranda de Duero) or sandstone with clay minerals matrix (samples from Ciudad Rodrigo). EXPERIMENTAL PROCEDURE Samples of ca 1–2 cm 2 in size and less than 5 mm in depth towards the substratum were collected. The analyses were Copyright  2008 John Wiley & Sons, Ltd.