Position-specific isotope fractionation in amino acids sorbed to ice: Implications for the preservation of isotopologue biosignatures

Fox, A. C.; Martineau, Estelle; Remaud, Gérald S.; Freeman, Katherine H.

doi:10.1016/j.gca.2021.06.023

Cited by 5 publications

(7 citation statements)

References 61 publications

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“…is an important strategy to infer the presence of life. Furthermore, position-specific isotopic analysis is an emerging powerful technique for understanding molecular formation pathway that allow for the discrimination between biotic and abiotic compounds (Tenailleau et al, 2004) and to provide contextual information about mineral-mediated reactions relevant to molecular formation in space environments (Fox et al, 2021). However, isotopic interpretations require knowledge of both the isotopic compositions of source materials and the process by which isotopes are fractionated .…”

Section: Terran-based Chemical Biosignatures Revealed By Mass Spectrometrymentioning

confidence: 99%

Planetary Mass Spectrometry for Agnostic Life Detection in the Solar System

Chou

Mahaffy

Trainer

et al. 2021

Front. Astron. Space Sci.

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For the past fifty years of space exploration, mass spectrometry has provided unique chemical and physical insights on the characteristics of other planetary bodies in the Solar System. A variety of mass spectrometer types, including magnetic sector, quadrupole, time-of-flight, and ion trap, have and will continue to deepen our understanding of the formation and evolution of exploration targets like the surfaces and atmospheres of planets and their moons. An important impetus for the continuing exploration of Mars, Europa, Enceladus, Titan, and Venus involves assessing the habitability of solar system bodies and, ultimately, the search for life—a monumental effort that can be advanced by mass spectrometry. Modern flight-capable mass spectrometers, in combination with various sample processing, separation, and ionization techniques enable sensitive detection of chemical biosignatures. While our canonical knowledge of biosignatures is rooted in Terran-based examples, agnostic approaches in astrobiology can cast a wider net, to search for signs of life that may not be based on Terran-like biochemistry. Here, we delve into the search for extraterrestrial chemical and morphological biosignatures and examine several possible approaches to agnostic life detection using mass spectrometry. We discuss how future missions can help ensure that our search strategies are inclusive of unfamiliar life forms.

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Section: Terran-based Chemical Biosignatures Revealed By Mass Spectrometrymentioning

confidence: 99%

Planetary Mass Spectrometry for Agnostic Life Detection in the Solar System

Chou

Mahaffy

Trainer

et al. 2021

Front. Astron. Space Sci.

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“…With its higher information content per molecule, position-specific isotope analysis ultimately provides much more detailed isotope information than traditional techniques. Methods for position-specific isotope analyses have utilized mass spectrometry, 5,9 carbon ( 13 C) nuclear magnetic resonance (NMR) spectroscopy, 8,10,11 and proton ( 1 H) NMR spectroscopy. 6,7 Traditional isotope (geo)chemistry has been primarily conducted using IRMS; however, NMR spectroscopy has the potential to play a key role within the field of position-specific carbon isotope analysis.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The 13 C/ 12 C abundance is usually reported using the delta notation ( δ 13 C) in units of permil [‰], measured relative to an analytical standard. However, traditional bulk or whole-molecule analysis provides only an average isotope abundance and thus masks the wealth of isotope information that is preserved at the individual carbon positions within complex organic molecules. − …”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Novel Nuclear Magnetic Resonance Method for Position-Specific Carbon Isotope Analysis of Organic Molecules with Significant Impurities

Rasmussen

Hoffman

2022

Anal. Chem.

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We introduce a novel nuclear magnetic resonance (NMR) tool for determining position-specific carbon (13C/12C) isotope ratios within complex organic molecules. This analytical advancement allows us to measure position-specific isotope ratios of samples that contain impurities with NMR peaks that overlap with the signals of interest. The method involves collecting a series of alternating 13C-coupled and 13C-decoupled 1H NMR spectra using an NMR pulse sequence designed to optimize temperature stability, followed by a data reduction scheme that allows the signals of interest to be isolated from signals of impurities. The method was validated using glycine reference materials with known 13C/12C ratios from the US Geological Survey (USGS) into which impurities typically found in amino acid samples were intentionally introduced. Following validation, the method was used to determine position-specific 13C/12C ratios in a set of USGS l-valine materials (USGS73, -74, -75) that contain significant impurities associated with their biological origin. The l-valines were found to contain distinct intramolecular isotope variability, and the 13Cα isotope spikes in USGS74 and USGS75 were clearly detected, where they preserve carbon isotope ratios of −4.8 ± 0.9‰ and +11.5 ± 0.8‰, respectively. Carbon isotope abundance at the beta and gamma positions indicates that the USGS73 l-valine was obtained from a different source than USGS74 and -75. This analytical approach is a significant step forward in the field of position-specific isotope analysis at natural abundance via NMR because it enables the investigation of samples that contain impurities which are typically present in samples derived from natural sources.

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“…In principle, it allows us to determine δ 13 C and δ 15 N values simultaneously, 30,31 although a larger amount of sample, more chemical reagents, and time-intensive laboratory work are required compared with GC/C/IRMS. 35,37 Moreover, underivatized individual AAs isolated using HPLC can be used for other isotope analyses, for example, radiocarbon analysis [38][39][40][41] and position-specific carbon isotope analysis, [42][43][44][45] which largely expands the possibilities of applications of HPLC-based methods.…”

mentioning

confidence: 99%

Application of a porous graphitic carbon column to carbon and nitrogen isotope analysis of underivatized individual amino acids using high‐performance liquid chromatography coupled with elemental analyzer/isotope ratio mass spectrometry

Sun

Ogawa

Ishikawa

et al. 2023

Rapid Comm Mass Spectrometry

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RationaleIsolation of underivatized amino acids (AAs) using high‐performance liquid chromatography (HPLC) is becoming a popular method for carbon (δ13C) and nitrogen isotope (δ15N) analyses of AAs because of the high analytical precision and for performing dual‐isotope analysis. However, some AAs in natural samples, especially small, hydrophilic AAs, are not suitably separated using reversed‐phase columns (e.g., C18) and ion‐exchange columns (e.g., Primesep A).MethodsWe developed a new method for HPLC using a porous graphitic carbon column for the separation of nine hydrophilic AAs. After purification, δ13C and δ15N values of AAs were determined using elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). We demonstrated the application of this method by determining δ13C and δ15N values of individual hydrophilic AAs in a biological sample, the muscle of blue mackerel (Scomber australasicus).ResultsChromatographically, the baseline separation of hydrophilic AAs was achieved in both the standard mixture and the biological sample. We confirmed that δ13C and δ15N values of AA standards remained unchanged during the whole experimental procedure. The δ13C values of AAs in mackerel muscle are also in good agreement with the values obtained using another verified method for δ13C analysis.ConclusionsThe good separation performance of hydrophilic AAs and the reliability of δ13C and δ15N analyses of individual AAs using the porous graphite column offer a significant advantage over conventional settings. We suggest that, in the future, the HPLC × EA/IRMS method can be used for reliable δ13C and δ15N analyses of AAs in natural samples.

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Position-specific isotope fractionation in amino acids sorbed to ice: Implications for the preservation of isotopologue biosignatures

Cited by 5 publications

References 61 publications

Planetary Mass Spectrometry for Agnostic Life Detection in the Solar System

Planetary Mass Spectrometry for Agnostic Life Detection in the Solar System

Novel Nuclear Magnetic Resonance Method for Position-Specific Carbon Isotope Analysis of Organic Molecules with Significant Impurities

Application of a porous graphitic carbon column to carbon and nitrogen isotope analysis of underivatized individual amino acids using high‐performance liquid chromatography coupled with elemental analyzer/isotope ratio mass spectrometry

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