Non‐innocent solvents in meteorite extractions: Evidence for artifact formation

Abstract Solvent extraction is a cornerstone of meteoritic organic and inorganic chemistry, yet the assumption that common solvents act as chemically inert media is becoming increasingly untenable. This study reports that low‐molecular‐weight alcohols, particularly methanol and ethanol, are “non‐innocent” solvents when used to extract soluble sulfur species from carbonaceous chondrites. Laboratory extractions of Tagish Lake and Allende samples demonstrate that these alcohols readily esterify meteoritic sulfate, producing large quantities of methyl and ethyl sulfate artifacts. Using isotopically labeled methanol (CD 3 OH) in 1:1 water mixtures, it is shown that >99% of the methyl sulfate signal previously attributed to indigenous methyl sulfate is actually solvent‐derived. Corrected abundances fall from hundreds of nmol g −1 reported in earlier studies to < 0.2 nmol g −1 , revealing that intrinsic methyl sulfate is only a trace constituent. Control experiments indicate that esterification requires both acidic conditions and solid meteoritic matrices, implicating Fe‐bearing phyllosilicates and oxides as heterogeneous catalysts. Additional experiments confirm that sulfate ester formation does not occur in solution‐only systems, underscoring the catalytic role of mineral–solvent interfaces. These findings not only necessitate a downward revision of reported organosulfur inventories in carbonaceous chondrites but also highlight a broader issue: solvent‐driven reactions can significantly alter the apparent chemical record of extraterrestrial materials. It is recommended that isotope‐labeled solvents and mixed‐solvent systems are employed as standard practice in future extractions, both to minimize artifact generation and to maximize analyte coverage across polarity ranges. Recognizing and mitigating solvent reactivity is essential for ensuring that laboratory analyses faithfully represent intrinsic extraterrestrial chemistry rather than experimental artifacts.