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The Mars Sample Return (MSR) is a near future mission to return samples from the surface of Mars to the Earth. The field operations to carry out data collection, selection of the samples, and sampling procedure, mainly related to the CanMars MSR analog mission, are well-studied and published. In contrast, studies related to the methodology implemented to characterize the mineralogy of the returned samples are scarcer and focused on biosignature detection. This work presents a non-destructive analytical methodology based on Raman microscopy (single point and imaging), micro-energy dispersive X-ray fluorescence imaging analysis, and scanning electron microscopy coupled to energy dispersive spectroscopy that could be used as a first analytical characterization for the Martian samples that will be returned to the Earth in the upcoming MSR mission, before any destructive analysis. The analytical methodology has been tested on a fragment of the Northwest Africa 1950 Martian meteorite, which gives us a mineralogical characterization of the meteorite. This methodology also allowed to define several chemical reactions taking place in some of the mineral phases (olivines and ilmenite) of the meteorite. In addition to the geochemical characterization of the samples, the fact that this methodology allows to assess the chemical transformations in several minerals gives important clues for describing mineral processes and geological evolution that took place on Mars. This work also shows the advantages and disadvantages that each of the techniques employed has when performing a mineralogical characterization, the information that each one can provide and the importance of combining them. This work has been financially supported through the RamOnMars project: “Contribution of the Raman spectroscopy to the exploration of Mars and Martian Moons: ExoMars, Mars 2020, and MMX missions” (Grant ESP2017-87690-C3-1-R), funded by the Spanish Ministry of Science and Innovation (MICINN) and the European Regional Development Fund (FEDER) and by the Spanish Agency for Research (AEI-MINECO/FEDER) through the Project Science and Instrumentation for the Study of (bio)geochemical processes in Mars (Sigue-Mars), Grant no. RED2018-102600-T. C. García-Florentino is grateful to the Basque Government for her Postdoctoral Grant. J. Huidobro is grateful to the Basque Government for her Predoctoral contract. I. Torre-Fdez acknowledges his predoctoral contract from the University of the Basque Country (UPV/EHU). J. Aramendia is grateful to the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 754513 and The Aarhus University Research Foundation for her fellowship. The authors thank the General Service of Electron Microscopy and Materials Microanalysis Laboratory from the SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) of the University of the Basque Country for their collaboration in the analyses.

[EN] The study of space has always been a field of great interest and thus space missions are becoming more and more ambitious with time. Therefore, with the 50th anniversary of the first spacecraft to land on Mars, a review about how traditional analytical techniques have been adapted to the era of in situ space exploration is presented. From the Viking Project to the future MMX mission, the techniques used for the in situ study of the geochemistry of the Martian surface is described. These techniques have been differentiated according to the type of analysis: elemental and molecular. On the one hand, among the elemental analytical techniques the XRF, APXS, ISE and LIBS stand out. On the other hand, GCMS, TEGA, MBS, XRD, Raman and IR spectroscopy have been the molecular techniques used in the missions to Mars. Miniaturization, real-time measurements, automation, low power consumption and reliability of operation under extreme conditions are some of the major challenges that analytical chemistry has faced as a result of the technological and scientific requirements of space missions. In this way, this review gathers all the in situ analytical techniques that have reached the surface of Mars onboard landers or rovers with the aim of studying its geochemistry. J. Huidobro is grateful to the Basque Government for her pre-doctoral contract. J. Aramendia is grateful to the European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No. 754513 and the Aarhus University Research Foundation for her fellowship.

[EN] Nowadays, miniaturization and portability are crucial characteristics that need to be considered for the development of water monitoring systems. In particular, the use of handheld technology, including microfluidics, is exponentially expanding due to its versatility, reduction of reagents and minimization of waste, fast analysis times and portability. Here, a hybrid handheld miniaturized polymer platform with a paper-based microfluidic device was developed for the simultaneous detection of nitrite and nitrate in real samples from both, fresh and seawaters. The platform contains an ionogel-based colorimetric sensor for nitrite detection and a paper-based microfluidic device for the in situ conversion of nitrate to nitrite. The platform was fully characterized in terms of its viability as a portable, cheap and quick pollutant detector at the point of need. The calibration was carried out by multivariate analysis of the color of the sensing areas obtained from a taken picture of the device. The limits of detection and quantification, for nitrite were 0.47 and 0.68mgL-1, while for nitrate were 2.3 and 3.4mgL-1, found to be within the limits allowed by the environmental authorities, for these two pollutants. Finally, the platform was validated with real water samples, demonstrating its potential to monitor nitrite and nitrate concentrations on-site as a first surveillance step before performing extensive analysis. This project has received funding from the European Union Seventh Framework Programme (FP7) for Research, Technological Development and Demonstration under grant agreement no. 604241. The funding support from Gobierno de España, Ministerio de Ciencia y Educación de España” under grant PID2020-120313 GB-I00/AIE/10.13039/501100011033, and Gobierno Vasco Dpto. Educación for the consolidation of the research groups (IT1271-19) are also acknowledged. RC-C acknowledges funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 778001. Special thanks to (SGIker) of the University of the Basque Country (UPV/EHU). FB-L and LB-D acknowledge the “Red de Microfluídica Española” RED2018-102829-T.

1. Introduction Olivine, (Mg, Fe)2SiO4, is a mineral composed of the two endmembers of its solid solution series: forsterite (Fo, Mg2SiO4) and fayalite (Fa, Fe2SiO4). It is a silicate mineral present in Mars usually alongside with plagioclase and pyroxene, as they are all present in basalts and igneous rocks. The forsterite and fayalite proportions in the olivine is a key factor in order to study this type of rocks. Active and upcoming Mars missions will study areas of ancient Mars using, among others, Raman spectroscopy in the instrumental payload, being a relevant technique for space exploration. There are several papers proposing Raman spectroscopy to quantify the ratio Fo/Fa based on the wavenumbers of the two most intense bands. However, the proposed calibration models have an uncertainty of around 10 %, too high to obtain reliable conclusions form the studied samples. In this work a new model that greatly improves the accuracy and uncertainty is presented. 2. Data set A collection of Raman spectra from olivines with a known composition was collected to develop a calibration model for the determination of the metallic content (Mg, Fe) of the mineral. The collection included 64 data points from 14 different research papers where different Raman instruments and acquisition parameters were used, which eliminates any possible bias that the instrumentation could introduce in the model. In addition to the set of olivines used for the calibration, a commercial pure olivine of known metallic concentration, Fo89.5±1.8Fa10.5±0.5, was used as the standard to validate the proposed models. This olivine was analyzed by WD-XRF and its mineral purity was checked by XRD. The Raman measurements were carried out with an Invia High Resolution micro-Raman spectrometer (Renishaw, UK) instrument, using a 532 nm excitation laser with a spectral resolution of 1 cm-1. 3. Results and Discussion Two different regression curves were developed to characterize the olivine concentration ratio by Raman spectroscopy using their two main Raman features (OB1, 812-825 cm-1, and OB2, 837-857 cm-1). These regression curves with their residuals can be observed in Figure 1 and Figure 2 and their equations are shown in Equation 1 and 2, respectively. The two red lines depicted in the calibration curve plots represent the calculated confidence interval for all the data at a 95 % confidence level. OB1 (cm-1) = 3.63·10-4·Fox2 + 0.0667·Fox + 814.2 (Equation 1) OB2 (cm-1) = 3.00·10-4·Fox2 + 0.142·Fox + 839.6 (Equation 2) As can be observed, all the data used to develop both models fit inside the confidence interval, which implies that there are not outliers among the set of data used. Regarding its quality parameters, the determination coefficient (r2) obtained for the quadratic regression models expressed in Equation 1 and 2 are 0.970 and 0.984, with a typical error of ±0.61 and ±0.73, respectively. The uncertainties in both residual plots scattered randomly, without showing any trend. In addition, all the points are equally distributed around the zero horizontal line and all of them are at the same range of distance from it. All of these facts implies that the proposed models for the data set used are the correct ones and that the model’s predictions should be correct on average, rather than systematically too high or too low. In order to check the accuracy of the two models, the standard commercial olivine described above was used (Fo89.5±1.8Fa10.5±0.5). The concentrations obtained using the OB1 and OB2 models can be observed in Table 1. As observed, the OB1 and OB2 forsterite confidence interval results overlap perfectly with the real concentration confidence interval, which means that the predicted concentrations with these two models were correct. In addition to the standard olivine, the calibration models were tested using the 64 data values that were used for their development. The wavenumber position of OB1 and OB2 were introduced in the respective regression curves and the forsterite value corresponding to each value was calculated. On average, it was observed that the OB1 model had better accuracy for the forsterite rich olivines, while the OB2 model was better for the fayalite rich olivines. Thus, as a good compromise solution, the best alternative would be to always use both models and to average their result, independently on the forsterite and fayalite concentrations of the mineral. This method was tested with the standard olivine, obtaining an uncertainty of ±2.1 % for the forsterite content and of ±2.0 % for the fayalite one. Uncertainties given with the 95 % level of confidence using expanded uncertainty (k=2). The proposed equations have been applied in the study of several Lunar and Martian meteorites where olivine is present. In the NWA 11273 Lunar meteorite olivine ranged from Fo56Fa44 to Fo83Fa17, a little bit broader than the values summarized in the Meteoritical Bulletin. In the NWA 10628 Martin shergottite, the Raman bands only showed the presence of fayalite, in agreement with the data from the Meteoritical Bulletin, while the Martian shergottites RBT 0462 gave a short range (Fo9.1±0.1Fa90.9±0.1), NWA 1950 a broader range (Fo60Fa40 to Fo80Fa20) and the DaG 735 the most extended range (Fo53Fa47 to Fo80Fa20). 4. Conclusions The study of olivines by the active and upcoming Mars missions could provide very relevant information about the evolution of the geology of Mars. One of the key parameters of this mineral is its metallic content, in other words, the ratio of forsterite and fayalite that compose them. In this work, a method to calculate that ratio by averaging the results of two calibration models that use the two main Raman bands of the mineral is proposed. With this method, an uncertainty of only 2 % is achieved, which is a significant improvement over the models already developed in literature, which have an uncertainty of around 10 %. With this model, it should be possible to provide an accurate olivine metallic characterization for the olivine Raman spectra that are found on Mars.

The SuperCam instrument suite provides the Mars 2020 rover, Perseverance, with a number of versatile remote-sensing techniques that can be used at long distance as well as within the robotic-arm workspace. These include laser-induced breakdown spectroscopy (LIBS), remote time-resolved Raman and luminescence spectroscopies, and visible and infrared (VISIR; separately referred to as VIS and IR) reflectance spectroscopy. A remote micro-imager (RMI) provides high-resolution color context imaging, and a microphone can be used as a stand-alone tool for environmental studies or to determine physical properties of rocks and soils from shock waves of laser-produced plasmas. SuperCam is built in three parts: The mast unit (MU), consisting of the laser, telescope, RMI, IR spectrometer, and associated electronics, is described in a companion paper. The on-board calibration targets are described in another companion paper. Here we describe SuperCam's body unit (BU) and testing of the integrated instrument. The BU, mounted inside the rover body, receives light from the MU via a 5.8 m optical fiber. The light is split into three wavelength bands by a demultiplexer, and is routed via fiber bundles to three optical spectrometers, two of which (UV and violet; 245-340 and 385-465 nm) are crossed Czerny-Turner reflection spectrometers, nearly identical to their counterparts on ChemCam. The third is a high-efficiency transmission spectrometer containing an optical intensifier capable of gating exposures to 100 ns or longer, with variable delay times relative to the laser pulse. This spectrometer covers 535-853 nm ( 105 - 7070 cm − 1 Raman shift relative to the 532 nm green laser beam) with 12 cm − 1 full-width at half-maximum peak resolution in the Raman fingerprint region. The BU electronics boards interface with the rover and control the instrument, returning data to the rover. Thermal systems maintain a warm temperature during cruise to Mars to avoid contamination on the optics, and cool the detectors during operations on Mars. Results obtained with the integrated instrument demonstrate its capabilities for LIBS, for which a library of 332 standards was developed. Examples of Raman and VISIR spectroscopy are shown, demonstrating clear mineral identification with both techniques. Luminescence spectra demonstrate the utility of having both spectral and temporal dimensions. Finally, RMI and microphone tests on the rover demonstrate the capabilities of these subsystems as well., Proyecto MINECO Retos de la Sociedad. Ref. ESP2017-87690-C3-1-R

International audience; The SuperCam instrument on the Perseverance Mars 2020 rover uses a pulsed 1064 nm laser to ablate targets at a distance and conduct laser induced breakdown spectroscopy (LIBS) by analyzing the light from the resulting plasma. SuperCam LIBS spectra are preprocessed to remove ambient light, noise, and the continuum signal present in LIBS observations. Prior to quantification, spectra are masked to remove noisier spectrometer regions and spectra are normalized to minimize signal fluctuations and effects of target distance. In some cases, the spectra are also standardized or binned prior to quantification. To determine quantitative elemental compositions of diverse geologic materials at Jezero crater, Mars, we use a suite of 1198 laboratory spectra of 334 well-characterized reference samples. The samples were selected to span a wide range of compositions and include typical silicate rocks, pure minerals (e.g., silicates, sulfates, carbonates, oxides), more unusual compositions (e.g., Mn ore and sodalite), and replicates of the sintered SuperCam calibration targets (SCCTs) onboard the rover. For each major element (SiO2, TiO2, Al2O3, FeOT, MgO, CaO, Na2O, K2O), the database was subdivided into five "folds" with similar distributions of the element of interest. One fold was held out as an independent test set, and the remaining four folds were used to optimize multivariate regression models relating the spectrum to the composition. We considered a variety of models, and selected several for further investigation for each element, based primarily on the root mean squared error of prediction (RMSEP) on the test set, when analyzed at 3 m. In cases with several models of comparable performance at 3 m, we incorporated the SCCT performance at different distances to choose the preferred model. Shortly after landing on Mars and collecting initial spectra of geologic targets, we selected one model per element. Subsequently, with additional data from geologic targets, some models were revised to ensure results that are more consistent with geochemical constraints. The calibration discussed here is a snapshot of an ongoing effort to deliver the most accurate chemical compositions with SuperCam LIBS.

Meteorites and impact glasses have been largely analysed using different techniques, but most studies have been focused on their geologicalemineralogical characterization and isotopic ratios, mainly of a destructive nature. However, much more information can be gained by applying novel non-destructive analytical procedures and techniques that have been scarcely used to analyse these materials. This overview presents some new methodologies to study these materials and compares these new approaches with the commonly used ones. Techniques such as X-Ray Fluorescence (XRF) and Laser Induced Breakdown Spectroscopy (LIBS), for elemental characterization, the hyphenated Raman spectroscopy- SEM/EDS and the combination of them, allow extracting simultaneous information from elemental, molecular and structural data of the studied sample; furthermore, the spectroscopic image capabilities of such techniques allow a better understanding of the mineralogical distribution. © 2017 Elsevier B.V. All rights reserved., Ministerio de Economía, Industria y Competitividad (project ESP2014-56138-C3-2-R)

A multianalytical study was proposed for the study of late-gothic wall paintings preserved inside the Romanic church of Saint Ementerio and Saint Celedonio of Goikolexea (Basque Country, Spain), erected in the 15th century and then renewed in the 17th. Raman spectroscopy coupled with energy-dispersive X-ray fluorescence was used in the in situ analysis in order to identify the nature of the original compounds and those used in the restoration works. The mortar composition and some original pigments (haematite, carbon black, cinnabar, goethite) were characterized. However, the identification of the original pictorial layer was difficult by the presence of chromatic retouching and mainly by the presence of the protective acrylic resin layer applied in modern times. Thus, the information obtained by the portable technique was used to select the sampling areas to perform laboratory Raman measurements especially in the green areas in which different shades appeared, because no antique green pigments were identified during the in situ analyses. Although the church was restored a couple of decades ago, the presence of salt crystallization was noted during the field campaign. Thus, some samples of salt efflorescences were collected to complete the analyses in the laboratory. Sulphate (calcium sulphate dihydrate CaSO4·2H2O and thenardite Na2SO4·10H2O) and nitrate compounds, (nitratine NaNO3 and nitromagnesite Mg(NO3)2·6H2O) were identified. Even, an extensive biodeterioration phenomenon was detected on the samples in the form of calcium oxalates whewellite and weddellite. All these decay products are strictly related to the characteristics of the surrounding natural environment and they represent the main factors that endanger the integrity of the masonry and consequently the substrate of the wall paintings. In particular, the presence of humidity of the walls and of the organic matter around the church seems to be the main factors of the formation of decay products. In addition, the hydrated sulphate copper connellite, generally identified as a product of corrosion of archaeological pieces in copper or bronze, was identified on the wall painting samples as a degradation product of malachite, the only original green pigment found in the mural paintings.

A multi-analytical approach based on the combined use of non-destructive spectroscopic techniques and micro-destructive techniques is presented, not only to characterize the mural paintings of Punta Begona galleries (Getxo, Biscay, Spain), but also to fill the gaps found in the historical documentation. The galleries were built in 1918 for Horacio Echevarrieta, a spanish republican businessman, and are in the list of protected historical buildings of the Basque Country. The whole building is composed by two galleries and a main hall with francoist iconographies in their walls, which disagree with the owner’s ideology, painted around 1938 after the occupation of the building in the Spanish Civil War. There is a lack of historical information about the original aspect of the mural paintings (1918 decoration) or the nature of the observable paintings (1938 over paintings). Thanks to the analysis carried out by optical microscopy, Raman spectroscopy, X-ray fluorescence (XRF), Fourier Transform Infrared spectroscopy (FTIR), Scanning electron microscopy coupled to electron scattering X-ray spectroscopy (SEM-EDS) and X-ray diffraction analysis (XRD), it was possible to identify under the painted layers a lead white preparation layer. Then, the original mural pigments were identified being of a silicate nature due to the systematic presence of presence of Clinochlore in all the colours. Regarding the over painted panels, their characterization revealed pigments that did not fit with the contemporaneous pigments, common practice in the francoism regime. In addition, carnauba wax could be identified as the binder. Moreover, the main decaying pathways of the materials were pointed out. These results will help to provide a new vision of these mural paintings, and the whole building. However, the most important achievement was the historical contextualisation of the main hall, which could help to change the historical perception of this heritage, putting the analytical chemistry at the service of history.

The landing site of the next planetary mission lead by ESA (ExoMars 2022) will be Oxia Planum. This location has been chosen due to different reasons, among them, the existence of sedimentary rocks that could host remains of organic matter. The fact that this type of rocks coexists with volcanic ones makes of high importance the study of the processes and the possible interactions that could happen among them. Therefore, in this research work the Armintza outcrop (Biscay, North of Spain) is proposed as an Oxia Planum analogue since it has the dichotomy of volcanic and sedimentary rock layers that is expected on the landing site of the ExoMars 2022 mission. As Raman and visible near infrared spectroscopies will be in the payload of the rover of that mission, they have been used to characterize the samples collected in the Armintza outcrop. With the help of these techniques, feldspars (albite mainly) and phyllosilicates (kaolinite and dickite, together with micas and chlorite minerals) have been identified as the major products on the samples, together with some weathering products (carbonates, sulphates, oxides) and apatite. Moreover, remains of kerogen have been detected in the sedimentary layers in contact with the interlayered lava flows, confirming the capability of similar sedimentary-volcanic layers to trap and store organic remains for millions of years. After establishing which compounds have volcanic or sedimentary origin, and which must be considered alteration phases, we can consider Armintza as a good Oxia Planum analogue.

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. En este trabajo, se han estudiado los procesos de degradación que tienen lugar en ladrillos expuestos a ambientes marinos. Teniendo en cuenta la importancia de este material de construcción en el que los silicatos presentes en el producto final actúan como estabilizadores en el propio material poroso, es necesario comprender los procesos de descomposición que se producen en estos entornos agresivos. Como se sabe, el aerosol marino transporta diferentes tipos de sales, tales como cloruros, sulfatos, nitratos, etc., presentes en el entorno circundante, lo que ejerce una influencia negativa en los materiales que producen los procesos de craqueo y desintegración del material y, en consecuencia, la pérdida de estabilidad de la pared de ladrillos. . Hoy en día, el desarrollo de dispositivos portátiles está cobrando mucha más importancia para ayudar a los investigadores a resolver problemas en el campo de una manera rápida y fácil. Con el fin de obtener resultados rápidos y satisfactorios sobre el estado de conservación de diferentes ladrillos de las galerías de Punta Begoña (Getxo, País Vasco, España), se desarrolló una metodología analítica in situ basada en el uso de fluorescencia de rayos X de dispersión de energía de mano. Espectrometría (HH-ED-XRF) asistida con otras técnicas de laboratorio (μ-ED-XRF y difracción de rayos X) para corroborar y complementar la información obtenida in situ. Esta construcción sufre la influencia de aerosoles marinos, puertos industriales, plantas de generación de energía y una refinería de combustible, entre otros. Las patologías visualmente observables en estos ladrillos son la desintegración, la ruptura y el desprendimiento de los ladrillos. La presencia de compuestos de deterioro en los ladrillos se ha estudiado de acuerdo con las orientaciones de los ladrillos dentro de la construcción.

The application of a non-destructive analytical procedure to characterise the mineral phases in meteorites is a key issue in order to preserve this type of scarce materials. In the present work, the Elephant Moraine 83227 meteorite, found in Antarctica in 1983 and originated from 4 Vesta asteroid, was analysed by micro-Raman spectroscopy, micro-energy-dispersive X-ray fluorescence and the structural and chemical analyser (Raman spectroscopy coupled with scanning electron microscopy-energy-dispersive spectroscopy) working in both point-by-point and image modes. The combination of all these techniques allows the extraction of, at the same time, elemental, molecular and structural data of the studied microscopic area of the meteorite. The most relevant results of the Elephant Moraine 83227 were the finding of tridymite for the first time in a 4 Vesta meteorite, along with quartz, which means that the meteorite suffered high temperatures at a certain point. Moreover, both feldspar and pyroxenewere found as the main mineral phases in the sample. Ilmenite, apatite, chromite and elemental sulphur were also detected as secondary minerals. Finally, calcite was found as a weathering product, which was probably formed in terrestrial weathering processes of the pyroxene present in the sample. Besides, Raman spectroscopy provided information about the conditions that the meteorite experienced; the displacements in some feldspar Raman bands were used to estimate the temperature and pressure conditions to which the Elephant Moraine 83227 was subjected, because we obtained both low and high formation temperature feldspar., Proyecto MINECO Retos de la Sociedad. Ref. ESP2014-56138-C3-2-R

Marine aerosol is a complex inorganic and organic chemistry system which contains several salts, mainly forming different type of salt clusters. Different meteorological parameters have a key role in the formation of these aggregates. The relative humidity (%RH), temperature, CO, SO2 and NOx levels and even the O3 levels can promote different chemical reactions giving rise to salt clusters with different morphology and sizes. Sulfates, nitrates and chlorides and even mixed chlorosulfates or nitrosulfates are the final compounds which can be found in environments with a direct influence of marine aerosol. In order to collect and analyze these types of compounds, the use of adequate samplers is crucial. In this work, salt clusters were collected thanks to the use of a self-made passive sampler (SMPS) installed in a 20th century historic building (Punta Begona Galleries, Getxo, Basque Country, Spain) which is surrounded by a beach and a sportive port. These salt clusters were finally analyzed directly by micro-Raman spectroscopy and Scanning Electron microscopy coupled to Energy Dispersive X-ray spectrometry (SEM-EDS).

The measurement of colour has been frequently used as an alternative to chemical analysis in a wide range of applications. Colorimetry and spectrophotometry are the reference techniques nowadays to measure colour. Practical problems arise, however, when granular, powdery, rough, curved or non-regular surfaces are processed. A standard digital camera, in combination with image analysis, can be used as an inexpensive, portable, non-destructive and fast analytical tool to measure colour but, surprisingly, this approach has not been fully exploited up to date. In this work, we have used this technique to measure tomato colour at different ripening stages. Spectrophotometric analysis of the extracts of the tomatoes allowed us to record the characteristic spectrum of each sample and correlate them with the chromaticity parameters by non-linear regression analysis of the whole data set. The resulting mathematical model showed a high power to discriminate between tomatoes, and was further used to produce a relative scale from zero to ten that enabled us to sort naturally matured tomatoes according to their ripening stage. In addition, the proposed model also allowed a fast estimation of the lycopene content in the samples, avoiding long and tedious extraction procedures, with a significant saving of time and reagents.

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.

The built Heritage constantly suffers different deterioration processes caused by the action of external agents, being one of the main consequences of the formation of soluble salts. These salts appear as efflorescences or subefflorescences that by hydration and dehydration cycles and/or dissolution processes producing crystallization of salts within the pores may promote internal fractures and material loss. The assessment of building material conservation on a 15th century Palace house, located close to the Urola river (Azpeitia, Basque Country, North of Spain), has been performed by in-situ characterization of pathologies on sandstone, mortar and limestone affected by infiltration waters. Portable Raman and X-ray fluorescence spectrometers have been used to characterize the bulk materials as well as the salts present along the different walls of the Palace. The in-situ analysis by those portable equipments has been complemented with laboratory measurements on selected samples, taken close to the spots analysed by the portable instruments. Different carbonates (natrite, termonatrite, natron, calcite and gaylussite), oxides (hematite, limonite and rutile), feldspar (orthoclase) and silicates (quartz) have been identified as original compounds. Furthermore, nitrates (niter, nitrocalcite and nitratine) and sulphates (gypsum and thenardite) have been found as decaying compounds permitting to establish the degradation processes of the attack produced by the infiltration waters on the different building materials. Moreover, the study revealed that certain materials used in a previous restoration produced new degradation processes, evidencing the importance of a proper selection of the materials to be used in the interventions. Copyright © 2013 John Wiley & Sons, Ltd.

Urban soils are potential reservoirs of toxic metals as a consequence of traffic emissions. Sources like brake linings, tyres, road pavement, exhaust fumes, guardrail, traffic signals and other galvanised steel structures are used in a large variety of external constructions in the modern urban areas. Their beneficial properties from a corrosion and oxidation perspective are well-known but less is known about their contribution to the environmental fate of corrosion-induced released zinc. In this work, the impact of guardrails and other traffic pollutants on urban soils has been studied by means of Raman spectroscopy (molecular speciation) and thermodynamic speciation to understand the mechanisms of metal release and uptake by the soils. Hydrozincite, Zn5(CO3)2(OH)6, was identified by means of Raman spectroscopy as the degradation compound of the galvanised zinc layer from guardrails which leads to the formation of soluble zinc, by acidic attack of the urban atmosphere, that drops and accumulate (zinc nitrate was identified) in soils. This fact shows the environmental risk of zinc release from the guardrails because zinc nitrate can be easily mobilised by water runoff, affecting the surrounding areas or groundwater. Other traffic pollutant that reaches guardrail and soil by atmospheric deposition, such as barium, was also identified in soil as well as in the guardrail in its carbonate form, BaCO3. Because of its low solubility, barium will accumulate in urban soils. Copyright © 2012 John Wiley & Sons, Ltd.

Due to high cost of certified reference materials (CRMs), reference materials (RMs) are preferred to check the method performance in environmental analysis. In this work, a laboratory reference material (LRM) was prepared and characterised to carry out the quality control in monitoring analysis of eight polycyclic aromatic hydrocarbons (PAHs) and nine trace metals in mussel tissue. Mussels were collected in a naturally polluted area. Before the reference material was bottled, the mussel tissue was stabilised by freeze-drying, ground and sieved. For the material characterisation, several statistical tests were applied to check the homogeneity of the analytes in the tissue, and a stability test was performed to study the effect of the storage temperature in the analyte concentration. Other characteristics such as specific density, moisture and lipid contents as well as particle size distribution of the material were determined. Although the LRM had a homogeneous distribution for all PAHs and almost all metals, the stability study showed different results at both storage temperatures studied. For both PAHs and trace metals, the material was suitable to assure the quality control of the analysis.

The aim of this work was to demonstrate that an archaeological ceramic piece has remained buried underground in the same stratum for centuries without being removed. For this purpose, a chemometric model based on Principal Component Analysis, Soft Independent Modelling of Class Analogy and Linear Discriminant Analysis classification techniques was created with the concentration of some selected elements of both soil of the stratum and soil adhered to the ceramic piece. Some ceramic pieces from four different stratigraphic units, coming from a roman archaeological site in Alava (North of Spain), and its respective stratum soils were collected. The soil adhered to the ceramic pieces was removed and treated in the same way as the soil from its respective stratum. The digestion was carried out following the US Environmental Pollution Agency EPA 3051A method. A total of 54 elements were determined in the extracts by a rapid screening inductively coupled plasma mass spectrometry method. After rejecting the major elements and those which could have changed from the original composition of the soils (migration or retention from/to the buried objects), the following elements (25) were finally taken into account to construct the model: Li, V, Co, As, Y, Nb, Sn, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Au, Th and U. A total of 33 subsamples were treated from 10 soils belonging to 4 different stratigraphic units. The final model groups and discriminate them in four groups, according to the stratigraphic unit, having both the stratum and soils adhered to the pieces falling down in the same group.

A new methodology is proposed in order to perform direct Raman measurements in sediments with high content in clay and organic matter with a reduced pre-treatment. Following this method, different compounds were found within the samples, some of them were assigned as natural compounds (clay, iron oxide, pyrite, aragonite, calcite, silicates and quartz) and the others were included in the group that comes from the human activity (titanium oxide, phthalocyanine blue, phthalocyanine green, gypsum, calcium arsenate, lead oxide, zinc oxide, sodium sulfide and iron hydroxioxide). The study of the presence of these polluting agents and their differentiation from the compounds that belong to the sediments as natural compounds is fundamental in order to understand the mobility/retention processes of the pollutants, and thus, their bioavailability. Also the speciation studies of solid phase downstream a wastewater treatment plant can be the basis to diagnose the adequate functioning of the facility. This work shows the applicability of Raman spectroscopy to perform speciation studies in the solid phases of natural and anthropogenic compounds present in river and estuarine sediments with appreciable content in clay and organic matter. The differentiation between natural and anthropogenic compounds is of fundamental interest because the potential toxicity of a metal (i.e. arsenic) in a natural compound (i.e. arsenopyrite) is not the same as in a newly formed synthetic compound in the river system due to an anthropogenic input (i.e. calcium arsenate). This illustrates the importance of the analysis of solid phases present in sediments because most of the polluting agents can be found in a different molecular configuration than the natural one. Copyright © 2008 John Wiley & Sons, Ltd.

In order to estimate the bioaccessibility of metals from mussel tissues, an in vitro physiologically based extraction test was applied to simulate the human gastrointestinal conditions. The samples were subjected to human body temperature, and Ag, Co, Cr, Cu, Mn, Ni, Pb and Sn were sequentially extracted with simulated gastric solution, followed by extraction with a simulated intestinal solution. Both gastric and intestinal extracted solutions and microwave-digested residue were analysed by ICP-MS. The procedure was applied to a certified reference material NIST 2977 (mussel tissue) to prove the accuracy of the method. Some mussel tissue samples from Northern Spain were subjected to this procedure to determine their metal content and their metal oral bioaccessibility.

The determination of Sn by flow injection–hydride generation–quartz furnace atomic absorption spectrometric (FI–HG–QFAAS) was optimised following different experimental designs. The best conditions were: 0.2% HCl (v/v), 0.5% NaBH4 (w/v) and the furnace temperature 875 °C. Under those conditions, the limit of detection was 0.17 ng dm−3 and a precision of 5.3% was obtained. One of the aims of this work was to optimise the closed vessel microwave assisted digestion (MAD) of sediments for the determination of Sn and Hg in the same extract using the analytical conditions previously optimised for Sn in the FI–QFAAS. The optimisation of the MAD of sediments was accomplished following a D-optimal design, including the composition of the HCl–HNO3 mixture, the pressure and irradiation time. However, we could not determine tin in the extracts due to the formation of foams, the optimisation of the digestion conditions were taken from the FI–cold vapour (CV)–QFAAS measurements of mercury. The optimum conditions were: 2.1 bar of pressure during 10 min of irradiation and two local optima composition of the acid mixtures: 80% HCl–20% HNO3 and 60% H2O–20% HCl–20% HNO3. The determination of mercury in sediments was validated with the CRM-580. In order to determine Sn in sediments the solutions from the same D-optimal design were analysed using an ICP-MS and the digestion conditions were optimised for Sn and for other 8 metals. In this case the same optimal conditions were obtained (2.1 bar and 10 min) but different acid mixture composition 20% HCl–80% HNO3. The determination of Sn and the other metals in sediments was validated using two other CRMs (PACS-2 and SGR-1).

Many different analytes are determined on a daily basis in many different matrices and the quality control (QC) for these determinations requires the use of reference materials (RMs), not only certified RMs (CRMs) but also laboratory RMs (LRMs) for routine purposes (e.g. control charting). In some cases, such materials are not available and the possibility of producing them in-house has to be considered. This article provides two examples showing that LRMs can be prepared by following a systematic approach without a very complex infrastructure: fly ash from cement manufacture; and, contaminated estuarine sediment.

In this chapter we review the applications of Raman spectroscopy and scanning electron microscopy for analysis of the road transport pollution. Raman spectroscopy has been applied on roadside soils and plants and on buildings facades in order to detect traffic emitted compounds. The emission of particles by diesel engines is another important field of study regarding to the air pollution in urban areas. In this sense, apart from Raman spectroscopy, the use of scanning electron microscopy coupled to Energy Dispersive X-ray Spectroscopy (SEM-EDS) plays an important role. In the literature appear several works which focus on the analysis of road dust; particles emitted by brake and tire wear are characterised by SEM images together with X-ray absorption spectra (EDS).

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.

Focused ultrasonic-assisted extraction (FUSE) is a new and particular technique based on the cavitation effect. In this work, the focused ultrasound assisted extraction was studied and developed for the extraction of polycyclic aromatic hydrocarbons from marine sediments and mussel tissues. The variables influencing the extraction (amplitude of the ultrasound pulse, the extraction time and the solvent) were studied by a full factorial design and a central composite design. As a result, flat response surfaces were obtained and the most convenient conditions were 45% of ultrasound amplitude, 120s of extraction time and 5 mL of acetone. Both accuracy and precision of the method were evaluated by means of two certified reference materials (marine sediment and mussel tissue) and the results were also compared to those obtained by microwave assisted extraction.