Prebiotic reactions on minerals

Model prebiotic reactions of formamide on granite have been followed by DESI MS imaging, showing that purine and pyrimidine nucleobases can be detected and that the mineral plays a catalytic role. Facundo Fernandez from the Georgia Institute of Technology, along with scientists from Blue Marble Institute of Space Science, NIST, and Scripps Institution of Oceanography are the first scientists to report the the direct detection of formamide reaction products on mineral surfaces, as they described in Analytical Chemistry.

Heterogeneous granites formed on Earth about 3.5-4 billion years ago, which is round about the period in which primitive life is thought to have begun. The team submerged pieces of cleaned granite into a beaker of formamide and heated them for 96 h at 160°. The samples were rinsed to remove the outer layers of formamide from the surface and analysed by desorption electrospray mass spectrometry while scanning across the surface.

The reaction products included purine, 5-azacytosine and formylpurine and their distributions varied with the mineral type across the surface. About 39% of the total product population was found on quartz sections, with 34% on orthoclase and 27% on biotite. Control experiments were carried out to confirm that the granite surface was necessary for the formation of the products.

The technique will help to study the prebiotic chemistry that went on to produce life on Earth. Formamide is the first hydrolysis product of hydrogen cyanide, which is thought to have been abundant in the atmosphere of early Earth, and could be a source of nucleobases. Now, the possibility of minerals acting as hosts or catalysts for these early reactions can be studied easily. The researchers concluded "We believe that the use of DESI MS imaging in the field of prebiotic chemistry will open new research possibilities, enabling the interrogation of new chemical systems."