A method for the automated Raman spectra acquisition.

Raman spectroscopy is a very powerful analytical technique with an increasing acceptance in the scientific community. For theoptimization of the Raman acquisition, two main parameters, the integration time and the number of accumulations, need tobe adjusted to the sample under analysis, as the sample, or even different spots on the same sample, can provide very differentRaman responses one from another. In this paper, we present a suite of algorithms to automate the acquisition parameteradjustment to the sample under analysis, addressing issues such as spectral saturation, fluorescence, cosmic ray detection andremoval, and adjustment of the acquisition parameters to optimize the acquired spectral data. This suite has been developedin the framework of the Raman Laser Spectrometer (RLS) instrument development for the Exomars mission but can be appliedto any Raman spectrometer. This will allow the spectrometer to adapt to the characteristics of the sample that is being analyzed,optimizing the total operative time, while improving the usability and overall efficiency of the system. Copyright © 2017 JohnWiley & Sons, Ltd.MINECO ESP2014-56138-C3-1-

Organic matter of fossil origin in the amberine speleothems from El Soplao Cave (Cantabria, Northern Spain)

Unusual amberine-coloured speleothems were recently found in El Soplao Cave (Cantabria, Spain). Chromophore elements such as Fe, Mn, Cd, Co or Ti were not present in significant quantities. Rather, our data show that their colour comes from leachates of fossilized organic material hosted in the carbonaceous Urgonian facies of the host rock. These leachates are related to the Cretaceous amber deposit that has been recently discovered in the vicinity of El Soplao Cave. The presence of humic and fulvic acids of fossil origin were confirmed by IR and Raman spectroscopic analysis of the carbonaceous strata and the speleothems. In addition, the mineralogy of the amberine speleothems was studied. Alternating bands made of calcite and aragonite reveal that periods of humidity and aridity occurred within the cave during the speleothem genesis

A Rich Morphological Diversity of Biosaline Drying Patterns Is Generated by Different Bacterial Species, Different Salts and Concentrations: Astrobiological Implications

Biosaline formations (BSFs) are complex self-organized biomineral patterns formed by ‘‘hibernating’’ bacteria as the biofilm that contains them dries out. They were initially described in drying biofilms of Escherichia coli cells + NaCl. Due to their intricate 3-D morphology and anhydrobiosis, these biomineralogical structures are of great interest in astrobiology. Here we report experimental data obtained with various alkali halide salts (NaF, NaCl, NaBr, LiCl, KCl, CsCl) on BSF formation with E. coli and Bacillus subtilis bacteria at two saline concentrations: 9 and 18 mg/mL. Our results indicate that, except for LiCl, which is inactive, all the salts assayed are active during BSF formation and capable of promoting the generation of distinctive drying patterns at each salt concentration. Remarkably, the BSFs produced by these two bacterial species produce characteristic architectural hallmarks as the BSF dries. The potential biogenicity of these biosaline drying patterns is studied, and the astrobiological implications of these findings are discusse

Combined vibrational, structural, elemental and Mössbauer spectroscopic analysis of natural phillipsite (zeolite) from historical eruptions in Tenerife, Canary Islands: Implication for Mars

The outcrop of “Las Arenas” volcano in Tenerife, Canary Islands (Spain) has been presented as Terrestrial volcanic analog for ancient Mars, showing a great variety of alteration processes and interesting mineralogy. The current analysis has been done by means of measurement techniques used or proposed on Martian studies. The new analysis of the zeolite has been carried out using Raman spectroscopy, Mössbauer spectroscopy, X-ray diffraction (XRD), Infrared spectroscopy, Laser induced breakdown spectroscopy and Scanning electron microscopy (SEM-EDX). The zeolite has been carefully analyzed using vibrational spectroscopy and it has been identified as Ca-phillipsite. The other techniques support and confirm the results. The measurements and results using the Raman Laser Spectrometer (RLS) simulator system show the capabilities RLS system in the ESA Exo- Mars mission. The chemometrical methods for the vibrational mineral detection show the advantages of Raman spectroscopy to understand the possible geological context. Furthermore, the proposed diagenesis and formation of the zeolites in southern part of Tenerife island have been confirmed by the twin space prototypes used. A new hypothesis about the origin for the special case of “Las Arenas” volcano Ca-phillipsite has been proposed. Finally, a multi-complementary comparison among the different techniques used on the current studie has been done and, also an analogy with the next space mission has been established. These analyses emphasize the strength of the different techniques and the working synergy of the different techniques together for planetary space missions

Amorphous zinc borate as a simple standard for baseline correction in Raman spectra

In this paper, our research group proposes a simple solution to a usual problem that appears in the Raman analysis of some substances, which is the presence of weak Raman signals, probably in combination with a high‐intensity luminescence background, affected by the presence of distortions in the baseline. Under this condition, the spectroscopist has to face spectra hard to edit and correct and thus hard to study. There are already some standard solutions that allow the correction of spectra from relative intensity to absolute intensity that also solves this problem and also allow quantitative analyses. But these solutions imply expensive standards or devices that could not be a worthy option when not working in absolute intensity or the Raman analyses stay at qualitative level and a quantitative study is not needed. The alternative Do It Yourself solution proposed in this paper is based on the use of amorphous zinc borate, an easy‐to‐find substance, which after a simple processing allows us to correct the baseline of Raman spectra qualitatively, offering a useful and economic reference when an absolute intensity correction is not needed. In order to evaluate the effectiveness of this procedure, some spectra were corrected using amorphous zinc borate and then compared the signal‐to‐noise ratio of some Raman signals before and after this correction. Copyright © 2017 John Wiley & Sons, Ltd.MINECO ESP2014-56138-C3-1-

In situ Raman characterization of minerals and degradation processes in a variety of cultural and geological heritage sites

Wetest the capabilities of in situ Raman spectroscopy for non-destructive analysis of degradation processes in invaluable masterpieces, as well as for the characterization of minerals and prehistoric rock-art in caves. To this end, we have studied the mechanism of decay suffered by the 15th-century limestone sculptures that decorate the retro-choir of Burgos Cathedral (N Spain). In situ Raman probe detected hydrated sulfate and nitrateminerals on the sculptures, which are responsible for the decay of the original limestone. In addition, in situ Raman analyses were performed on unique speleothems in El Soplao Cave (Cantabria, N Spain) and in the Gruta de las Maravillas (Aracena, SWSpain). Unusual cavemineralswere detected in El Soplao Cave, such as hydromagnesite (Mg5(CO3)4(OH)2·4H2O), as well as ferromanganese oxides in the black biogenic speleothems recently discovered in this cavern. In the Gruta de las Maravillas, gypsum (CaSO4·2H2O) was identified for the first time, as part of the oldest cave materials, so providing additional evidence of hypogenic mechanisms that occurred in this cave during earlier stages of its formation. Finally, we present preliminary analyses of several cave paintings in the renowned “Polychrome Hall” of Altamira Cave (Cantabria, N. Spain). Hematite (Fe2O3) is the most abundant mineral phase, which provides the characteristic ochre-reddish color to the Altamira bison and deer paintings. Thus, portable Raman spectroscopy is demonstrated to be an analytical technique compatible with preserving our cultural and natural heritage, since the analysis does not require physical contact between the Raman head and the analyzed items

Surface and microstructural failures of PET-Coated ECCS plates by salmon-polymer interaction

Producción CientíficaThe new types of knowledge-intensive, multilayer containers consist of steel plates protected against corrosion by nanometric electrolytic chromium (Cr0) and chromium oxide (Cr2O3) layers chemically bonded to polyethylene terephthalate (PET) polymer coating to preserve food. It was observed that after emptying the cans, the salmon adhered to the polymer coating, changing its color, and that this adhesion increased with longer storage times. This work was aimed at determining the product-container interactions and their characterization by X-ray diffraction (XRD), confocal Raman and micro-Raman imaging and scanning electron microscopy (SEM) analysis. The zones of adhesion showed surface changes, variations in crystallinity and microstructural degradation of the PET coating. In addition, localized damages altering the functional properties of the multilayer system were observed as microcracking in the chromium layers that protect the steel. The degradation undergone was evaluated and characterized at a surface and microstructural level to establish the failure mechanisms, which were mainly associated with the activity of the adhered muscle and its biochemical components. Finally, a recommendation is done to preserve the useful life and functionality of cans for the preservation and efficient use of resources with an impact on recycling and environmental conservancy.The authors gratefully acknowledge the Fondecyt Program of Conicyt Chile for the financial support through Grant No. 1130634 and the special contribution of University Austral of Chile

Analysis and adsorption-interaction of amino acids on basaltic mineral subjected to different simulated atmospheres

[EN] The research have been conducted in order to have a better understanding of amino acid adsorption on volcanic matrix surface subjected to different extreme environmental conditions (Martian surface environment, space environment, UV-environment, etc.) simulated by The Planetary Atmosphere and Surfaces Chamber (PASC) at the ”INTA-Centro de Astrobiogia”. The spectroscopic measurements were done by Raman and IR spectroscopy (at the Unidad Asociada Uva-CSIC at Centro de Astrobiología) taking into account the capabilities of the combined Raman-IR analyses for astrobiological target such as the detection of biomarkers on the future ESA-ExoMars Mission. Moreover, SEM-EDX analyses have been conducted in order to complement the spectroscopic results, which endeavour the use of spectroscopic systems for space missions. Conclusion: The L-aspartic acid shows to be the most suitable amino acid for this kind of experiment; the amino acid half–life is 104 seconds according to the reference; both spectroscopic techniques, working in synergy, have detected the amino acid degradation, but amino acid mineral interaction was not detected; the experiments have shown the versatility of the simulation chamber (PASC) to perform experiments under different planetary environments.[ES] Los experimentos se han realizado con el objectivo de tener un mejor entendimiento sobre aminoácidos inmovilizados sobre matrices de caracter volcánico y estos han sido sometidos a diferentes ambientes extremos (Ambiente marciano, ambiente espacial, ambiente de radiación UV, etc.) dentro de la Cámara de Simulación de atmosferas y superficies planetarias (PASC) en el Centro de Astrobiología- INTA. Los métodos espectroscópicos usados son la espectroscopía Raman e Infrarroja (en la Unidad Asociada Uva-CSIC al Centro de Astrobiología) teniendo en cuenta las capacidades combinadas de estos sistemas para objetivos astrobiológicos como la detección de biomarcadores en la futura misión ESAExoMars. Además, se realizaron medidas mediante microscopía electrónica (SEM-EDX) las cuales complementan los resultados espectroscópicos y refuerzan el uso de estos sistemas para misiones espaciales. Conclusiones: El ácido L-Aspartico demostró ser el más eficiente para este tipo de experimentos; la vida media de los aminoácido es de 104 teniendo en cuenta las referencias; ambos sistemas espectroscópicos Raman-IR, trabajando conjuntamente, detectaron la degradación de los aminoácidos, pero la interacción entre aminoácido-mineral no fue detectada; los experimentos demostraron la versatilidad de la Cámara de Simulación (PASC) en cuanto a la realizacion de experimentos en distintos ambientes planetarios.Peer reviewe