Analytical Characterization Approaches to Measure Prebiotic-Synthesis Products in Salty Environments

Experiments exploring potential emergence-of-life chemistry in a laboratory setting critically depend on simulating realistic early-Earth environments. Such experimental conditions include the implementation of controlled high temperatures and pressures, anoxic gas phases, saline fluids, and diverse mixtures of low-concentration organic compounds.

Common analytical methods, like mass spectrometry (MS) and gas chromatography (GC), often require desalting and derivatization processing steps prior to analysis. These preprocessing steps are not always amenable to non-targeted analyses or quantification of low concentrations of organic compounds in complex mixtures.

Here, we explore the use of two analytical methods to measure simple organic molecules in highly saline aqueous solutions (ca. 0.5 M), which were likely in seawater-associated early-Earth environments. Specifically, Direct Analysis in Real Time (DART)-MS and Nuclear Magnetic Resonance (NMR) spectroscopy were used as independent analyses with minimal sample processing to detect and identify glycine, glycolic acid, acetone, acetic acid, propionic acid, methylsulfonic acid and methylbutanoic acid.

Such small soluble organic compounds could have been found in concentrations below 100 µM on the early Earth. The performance of each analytical method was assessed, and it was found that they can be used in conjunction to obtain semi-quantitative information about each analyte of interest.

Additionally, the same techniques were applied to the analysis of a hydrothermally altered version of the sample subjected to 150 °C and 500 bar. Results show that DART-MS and NMR have the potential to help interrogate complex samples through untargeted analyses.

Analytical Characterization Approaches to Measure Prebiotic-Synthesis Products in Salty Environments, chemrxiv.org

Astrobiology,