In situ DRIFT, Raman, and XRF implementation in a multianalytical methodology to diagnose the impact suffered by built heritage in urban atmospheres.

This work addresses the evaluation of an innovative mutianalytical method to assess the conservation state of a fifteenth century palace house. With the goal of reducing the handicaps of field analysis, the in situ spectroscopic assessment, often based on the use of X-ray fluorescence and Raman spectrometers, was complemented by the use of diffuse reflectance infrared Fourier transform spectroscopy. In this manner, its usefulness as a diagnostic tool to discover the origin and mechanisms of the damage caused by atmospheric and infiltration water attacks were thoroughly examined. Moreover, the study was extended in the laboratory to increase the information obtained by nondestructive techniques. The results revealed a severe material loss caused by soluble salts. Thus, a noninvasive sampling method using cellulose patches was tested to study the amount and mobility of salts by means of ion chromatography. Finally, to establish the chemical degradation processes that are occurring in the palace, a chemometric analysis of the quantitative data as well as the construction of thermodynamic models was done to advise on the required restorative actions. Graphical Abstract The different phases of the multianalytical method to assess the conservation state of built heritage.

Sample pretreatment to differentiate between bioconcentration and atmospheric deposition of polycyclic aromatic hydrocarbons in mosses.

In this first approach a comparison using different sample pretreatment methodologies has been made to differentiate between total atmospheric deposition and bioconcentration of polycyclic aromatic hydrocarbons (PAHs) in moss samples (Brachythecium rutabulum). Samples were collected in a densely polluted urban area in Barakaldo (Biscay, Basque Country) and submitted to different cleaning procedures with the aim to remove as many deposited atmospheric particles as possible. Analysis by means of Scanning Electron Microscopy coupled to Energy Dispersive Spectroscopy (SEM-EDS) allowed to quantify the removal efficiency of each cleaning procedure and to chemically characterise particles still present in the pre-cleaned sample. Cleaning moss samples twice with deionised water in an ultrasound bath showed up as the most suitable way to remove solid particles deposited on their surface. Discerning between bioconcentration and atmospheric deposition is therefore possible after GC-MS quantitative analysis of non-washed and washed moss samples.

Applicability of a Diffuse Reflectance Infrared Fourier Transform handheld spectrometer to perform in situ analyses on Cultural Heritage materials.

This work studies the applicability of a Diffuse Reflectance Infrared Fourier Transform handheld device to perform in situ analyses on Cultural Heritage assets. This portable diffuse reflectance spectrometer has been used to characterise and diagnose the conservation state of (a) building materials of the Guevara Palace (15th century, Segura, Basque Country, Spain) and (b) different 19th century wallpapers manufactured by the Santa Isabel factory (Vitoria-Gasteiz, Basque Country, Spain) and by the well known Dufour and Leroy manufacturers (Paris, France), all of them belonging to the Torre de los Varona Castle (Villanañe, Basque Country, Spain). In all cases, in situ measurements were carried out and also a few samples were collected and measured in the laboratory by diffuse reflectance spectroscopy (DRIFT) in order to validate the information obtained by the handheld instrument. In the analyses performed in situ, distortions in the diffuse reflectance spectra can be observed due to the presence of specular reflection, showing the inverted bands caused by the Reststrahlen effect, in particular on those IR bands with the highest absorption coefficients. This paper concludes that the results obtained in situ by a diffuse reflectance handheld device are comparable to those obtained with laboratory diffuse reflectance spectroscopy equipment and proposes a few guidelines to acquire good spectra in the field, minimising the influence caused by the specular reflection.

Determination of the pigments present in a wallpaper of the middle nineteenth century: the combination of mid-diffuse reflectance and far infrared spectroscopies.

In this work the determination of the pigments present in a decorative wallpaper of the middle nineteenth century from the Santa Isabel factory (Vitoria-Gasteiz, Basque Country, Spain) has been performed by a combination of mid-Diffuse Reflectance Infrared Spectroscopy (DRIFT) and Far Infrared Spectroscopy (FIR) in transmission mode. The DRIFT is a powerful infrared technique that is not widely used in the analyses of artworks in spite of being especially adequate for powdered samples. In this mode, sample pretreatment is not required and the obtained spectra are easier to solve than those obtained in transmittance mode. Those pigments which are not active in the mid-infrared region may be determined easily by FIR. In the last decade, in the field of painted materials very few studies performed by far infrared spectroscopy and mid infrared spectroscopy in diffuse reflectance mode can be found. In most of them the researchers have used one of these techniques, but in no case the combination of both. As we demonstrate in this work, combining these two techniques a complete characterization of the wallpaper can be carried out. Small samples were collected from the wallpaper for the analysis of the rose, brown, yellow and blue colours. In this way, minium (Pb3O4), calcite (CaCO3), barium sulphate (BaSO4), prussian blue (Fe7C18N18), iron oxide yellow (α-FeOOH), vermillion (HgS) and carbon black pigment from organic origen were detected. Finally, the validation was carried out by XRF and Raman spectroscopy getting the same results as with the combination of diffuse reflectance infrared spectroscopy and far infrared spectroscopy.

Diagnosing the traffic impact on roadside soils through a multianalytical data analysis of the concentration profiles of traffic-related elements.

The road traffic has become one of the most serious environmental problems in many cities and the main source of pollution of urban soils. To diagnose properly the magnitude of such impacts on roadside soils, eight urban and metropolitan soils were selected as a function of traffic density, distance to the road and years of operation, for which the concentration of 60 elements (major, minor and trace elements) were measured by semi-quantitative ICP-MS after acid digestion, as a first step in assessing the traffic impact. With this information, a comprehensive study was carried out focusing on the quantitative analysis of the concentration of 46 elements from the 8 sampling areas, analyzing the vertical and horizontal distributions of the metals in the roadside soils. The chemometric analysis showed that only the traffic-related elements accumulate in topsoil and present a high decreasing profile with depth and the distance to the road; however, this clear behavior takes places only in old roads that have undergone the traffic impact for a long time, but not in new roads or roads with low traffic density. Finally, the geoaccumulation indexes are suggested to be used instead of the local guidelines to assess the pollution state of the roadside soils, especially for the emerging trace elements like Antimony.