RT Journal Article
T1 Detection of indigenous organic matter in rocks from the interpretation of carbon molecular forms in the laser-induced plasma
A1 García-Gómez, Laura
A1 Delgado-Pérez, Tomás
A1 Fortes-Román, Francisco Javier
A1 Cabalín-Robles, Luisa María
A1 Laserna-Vázquez, José Javier
K1 Química analítica
AB Detection of indigenous organic matter (IOM) in rocks using molecular-laser-induced breakdown spectroscopy (LIBS) is reported. IOM refers to carbon-based compounds of variable complexity intimately associated with mineral and amorphous phases both in condensed phases and in a dispersed state spatially associated to mineral aggregates. The presence of IOM may provide valuable information in astrobiology about the possibility of past or present life on planetary bodies. Kerogen, charcoal, bitumen, and graphite are only some examples of IOM that may appear in rocks. This paper reports the detection of kerogen in oil shale (a sedimentary rock also containing dolomite, calcite, pyrite, quartz, and albite) from the LIBS study of CN and C2 emissions under simulated Martian conditions. A set of oil shale samples with variable concentrations of total organic carbon (TOC) ranging from 2.78% to 12.74% were analyzed. A careful LIBS analysis of molecular species associated within hydrocarbons confirmed the presence of organic matter derived from kerogen. A linear correlation between the CN and C2 emissions and the %TOC was observed. Using a simulated Martian atmosphere as surrounding gas, the limit of detection for organic matter was calculated in 0.42% TOC. Additionally, the potential interferences in geological samples for LIBS detection of molecular species were also evaluated. Results demonstrate that common elements in rocks such as Ca, Fe, K, Mg, Na and Si do not interfere with the detection of organics. In contrast, Ti at concentrations above 0.4% may induce false positive results using the CN emission at 388.34 nm. To overcome this inconvenience, the CN emission at 387.14 nm may be used which, although less sensitive, is free from titanium interference.
PB Elsevier
YR 2024
FD 2024-01-19
LK https://hdl.handle.net/10630/30399
UL https://hdl.handle.net/10630/30399
LA eng
NO Laura García-Gómez, Tomás Delgado, Francisco J. Fortes, Luisa M. Cabalín, Javier Laserna, Detection of indigenous organic matter in rocks from the interpretation of carbon molecular forms in the laser-induced plasma, Spectrochimica Acta Part B: Atomic Spectroscopy, Volume 213, 2024, 106861, ISSN 0584-8547, https://doi.org/10.1016/j.sab.2024.106861
NO Funding for open Access charge: Universidad de Málaga / CBUA.This work was supported by Programa Operativo FEDER Andalucía 2014–2020, Consejería de Economía y Conocimiento de la Junta de Andalucía, Reference UMA18-FEDERJA-272 and by Project PID2020-119185GB-I00 from the Ministerio de Economia y Competitividad of Spain. An author, L. García-G´omez, is grateful to the Spanish Ministerio de Economia y Competitividad for the concession of a FPI grant from Project PID2020-119185GB-I00.
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 21 ene 2026