Mobile Raman spectroscopy in astrobiology research

Abstract

Raman spectroscopy has proved to be a very useful technique in astrobiology research. Especially, working with mobile instrumentation during fieldwork can provide useful experiences in this field. In this work, we provide an overview of some important aspects of this research and, apart from defining different types of mobile Raman spectrometers, we highlight different reasons for this research. These include gathering experience and testing of mobile instruments, the selection of target molecules and to develop optimal data processing techniques for the identification of the spectra. We also identify the analytical techniques that it would be most appropriate to combine with Raman spectroscopy to maximize the obtained information and the synergy that exists with Raman spectroscopy research in other research areas, such as archaeometry and forensics.

A comparative mobile Raman study for the on field analysis of the Mosaico de los Amores of the Cástulo Archaeological Site (Linares, Spain)

“…Three of the spectrometers (EZRaman-I dual, i-Raman ® EX, and BWS445-785S InnoRam ™ ) were portable, [14,15] operated with or without battery, coupled with long fibre optics cables that allowed the measurements to be conducted remotely. In general, this kind of Raman spectrometers, which are medium weighted (expected from the EZRaman-I dual system that includes two spectrometers in its packaging) and can be transported by one person on site, are preferred in archaeometrical studies.…”

“…In general, this kind of Raman spectrometers, which are medium weighted (expected from the EZRaman-I dual system that includes two spectrometers in its packaging) and can be transported by one person on site, are preferred in archaeometrical studies. [14,15] The coupling of the fibre optics cables is an advantageous property, as the probe can be positioned and focus by several ways (e.g., microscope, translation stage, tripod, articulated arm, or manual). The longer the fibre optics, the easier the positioning of the probe on large-scale objects (wall paintings, sculptures, etc.)…”

“…Palm and ultra-mobile Raman instruments, found commercially available, are further miniaturize. [14,15] In this study, four mobile Raman instruments, namely, the EZRaman-I dual Raman analyser from TSI Inc. (USA), the i-Raman ® EX from BWTEK (USA), the BWS445-785S InnoRam ™ Raman spectrometer from BWTEK (USA), and the Bravo Raman spectrometer from Bruker (Europe), which have different laser wavelengths and technologies, are compared and evaluated in the case of colourful tesserae from the Mosaico de los Amores (Linares, Spain). Also, their applicability on measuring in open air environments is examined.…”

Water Quantification of Amorphous and Crystalline Ferric Sulfates Relevant to Mars

“…Although significant amounts of sulfates have been found on the Martian surface, more experimental data are needed to confirm which sulfates are present and to extract information about historical hydration levels and the possibility of supporting life on Mars (King et al, 2010;Lane et al, 2008;Sobron et al, 2012). Raman spectroscopy, which can provide detailed information about chemical structures, phases and polymorphs, crystallinity and molecular interactions, is an ideal tool for microscopic sample analysis of rock samples collected from the surface of Mars (Chou et al, 2013;Vandenabeele et al, 2014;Wang et al, 2015). Raman spectra contain a series of features corresponding to different vibrational modes in molecules.…”

Analytical strategy for representative subsampling of Raman‐based robotic planetary exploration missions: The case study of solid dispersions of β‐carotene and L‐cysteine in gypsum

“…However, the methodology should also integrate the technical constraints inherent with robotic space missions, in particular the limitation associated with miniaturised instrumentation (limited weight and size, which impact the spectral resolution and enlarge the laser footprint on the sample) and energy availability. [28][29][30] Consequently, on Mars, only a limited number of spectra will be acquired per sample. The ExoMars RLS is expected to take 20 spectra over the sample surface in its automatic mode, [7] whereas the SHERLOC Raman instrument on board the Mars 2020 rover is expected to analyse a sample area of 1 mm 2 with a spectrum recorded every 50 μm in a micromapping mode.…”