TY - JOUR
T1 - Investigating the impact of x-ray computed tomography imaging on soluble organic matter in the Murchison meteorite
T2 - Implications for Bennu sample analyses
AU - Glavin, Daniel P.
AU - Eckley, Scott A.
AU - Aponte, José C.
AU - Berger, Eve L.
AU - Burton, Aaron S.
AU - Dworkin, Jason P.
AU - Elsila, Jamie E.
AU - Ferguson, Frank T.
AU - Furukawa, Yoshihiro
AU - Graham, Heather V.
AU - Koga, Toshiki
AU - Liss, Michael
AU - McLain, Hannah L.
AU - Naraoka, Hiroshi
AU - Oba, Yasuhiro
AU - Parker, Eric T.
AU - Righter, Kevin
AU - Schmitt-Kopplin, Philippe
AU - Simkus, Danielle N.
AU - Takano, Yoshinori
AU - Connolly, Harold C.
AU - Lauretta, Dante S.
N1 - Publisher Copyright:
© 2023 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
PY - 2024/1
Y1 - 2024/1
N2 - X-ray computed tomography (XCT) is a valuable reconnaissance tool for three-dimensional imaging and identification of distinct lithologies in extraterrestrial samples. It will be used as part of the preliminary examination of samples returned from asteroid (101955) Bennu by the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission. However, it must first be established whether x-rays generated during XCT could degrade or alter the organic composition of the returned samples by radiolysis. To test this, we split a crushed sample of the Murchison CM2 meteorite, kept one portion as a control, and irradiated the other portion up to the maximum x-ray dosage (~180 Gy) that a Bennu sample would experience during an XCT imaging experiment. We then extracted organic compounds from both splits and conducted (i) nontargeted soluble organic analyses to compare the chemical distributions of C-, H-, O-, N-, and S-bearing species and (ii) targeted measurements to quantify the abundances of 96 individual soluble organic molecules that included protein amino acids, amines, carboxylic acids, hydroxy acids, carbonyl compounds, polycyclic aromatic hydrocarbons, alcohols, sugars, and N-heterocycles. We found that XCT imaging of the Murchison meteorite had no measurable impact on the relative abundances or enantiomeric compositions of most of the soluble organic compounds targeted in this study. Elevated total abundances of several soluble organic compound classes were observed in the XCT-scanned Murchison sample relative to the control. This is likely related to particle size heterogeneity and specific surface area differences between the sample aliquots used for the extractions, rather than a result of the x-ray exposure. Assuming the samples returned from asteroid Bennu by OSIRIS-REx have a similar composition to carbonaceous chondrites, these data provide confidence that XCT will not significantly alter their soluble organic compositions.
AB - X-ray computed tomography (XCT) is a valuable reconnaissance tool for three-dimensional imaging and identification of distinct lithologies in extraterrestrial samples. It will be used as part of the preliminary examination of samples returned from asteroid (101955) Bennu by the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission. However, it must first be established whether x-rays generated during XCT could degrade or alter the organic composition of the returned samples by radiolysis. To test this, we split a crushed sample of the Murchison CM2 meteorite, kept one portion as a control, and irradiated the other portion up to the maximum x-ray dosage (~180 Gy) that a Bennu sample would experience during an XCT imaging experiment. We then extracted organic compounds from both splits and conducted (i) nontargeted soluble organic analyses to compare the chemical distributions of C-, H-, O-, N-, and S-bearing species and (ii) targeted measurements to quantify the abundances of 96 individual soluble organic molecules that included protein amino acids, amines, carboxylic acids, hydroxy acids, carbonyl compounds, polycyclic aromatic hydrocarbons, alcohols, sugars, and N-heterocycles. We found that XCT imaging of the Murchison meteorite had no measurable impact on the relative abundances or enantiomeric compositions of most of the soluble organic compounds targeted in this study. Elevated total abundances of several soluble organic compound classes were observed in the XCT-scanned Murchison sample relative to the control. This is likely related to particle size heterogeneity and specific surface area differences between the sample aliquots used for the extractions, rather than a result of the x-ray exposure. Assuming the samples returned from asteroid Bennu by OSIRIS-REx have a similar composition to carbonaceous chondrites, these data provide confidence that XCT will not significantly alter their soluble organic compositions.
UR - https://www.scopus.com/pages/publications/85179992608
U2 - 10.1111/maps.14111
DO - 10.1111/maps.14111
M3 - Article
AN - SCOPUS:85179992608
SN - 1086-9379
VL - 59
SP - 105
EP - 133
JO - Meteoritics and Planetary Science
JF - Meteoritics and Planetary Science
IS - 1
ER -