ORIGIN: Laser Desorption Ionization Mass Spectrometry of Nucleobases for In Situ Space Exploration

Abstract

The ORganics Information Gathering INstrument (ORIGIN) is a space-prototype laser desorption ionization mass spectrometer designed to analyze molecular biosignatures. Nucleobases, fundamental components of nucleic acids, have been found in carbonaceous meteorites and in returned samples from the asteroid Ryugu, which suggest their extraterrestrial origin and possibly their significance in prebiotic chemistry and the RNA world hypothesis. Therefore, future space missions should be equipped for the in situ detection of nucleobases at relevant concentrations. This study investigated six nucleobases—adenine, cytosine, 5-methylcytosine, guanine, thymine, and uracil—using the ORIGIN setup. All six are readily detected and identified, with the mass spectra showing parent ions and minimal fragmentation. Mixture analyses illustrate the instrument's quantitative potential. The detection limit for adenine was 52 fmol mm-2, and we show that sensitivity can be further improved by increasing detector voltage and sampling more positions. This study demonstrates ORIGIN’s capability to detect nucleobases at trace abundance levels. The detection of nucleobases and other molecular biosignatures on other planetary objects might offer new insights into the origin of life on Earth and the possibility of discovering life beyond our planet.