Enantioselective Gas Chromatography In Search Of The Origin Of Biomolecular Asymmetry In Outer Space

Since the pioneering work of Emanuel Gil-Av and his associates at the Weizmann Institute of Science the direct gas chromatographic resolution of enantiomers has found its application in different fields of natural sciences, even expanding to space research and astrobiology. In these domains the resolution of chiral molecules of prebiotic relevance is of particular interest, since the determination of ratios between l-and d-enantiomers within non-terrestrial samples is assumed to shed light on the origin of biomolecular homochirality and the beginnings of life itself. According to an astrophysical scenario, the first molecular symmetry breaking event occurred upon irradiation of chiral organic molecules with circularly polarized light present in the interstellar medium. To examine this hypothesis, among others, chiral gas chromatographic stationary phases have been widely used to provide the differentiation of enantiomers in extracts of meteorites, samples of simulated interstellar ices and Mars soil analogues. Moreover several chiral capillary columns have been selected for in situ analyses of extraterrestrial organic matter by Mars missions and the cometary Rosetta mission. This review will highlight current advances of enantioselective gas chromatography applied to space science.