Adenine adsorption on and release from meteorite specimens assessed by surface-enhanced Raman spectroscopy

The trapping of organic molecules in minerals is considered to be an initial step in the genesis of life. We have previously explored the adsorption of adenine and RNA on clay. We have now used surface-enhanced Raman spectroscopy (SERS) to characterize adenine adsorption on and release from specimens of two meteorites, the Zagami Martian meteorite and the Murchison meteorite. Powdered meteoritic material was incubated with very dilute adenine solutions. An adenine SER response of the resulting supernatant weaker than that of the initial solution indicated that adenine was bound to the meteorite. A SER signal with the pellet meant that adenine that was initially adsorbed on it was transferred to the silver colloid SER probe. Adenine adsorption on and release from the Murchison carbonaceous chondrite and the mineral Zagami meteorite depended on the composition of the meteorites. Adenine was much more strongly bound to the Murchison meteorite, which contains bioorganic matter, than to the purely mineral Zagami meteorite. Copyright (C) 2004 John Wiley Sons, Ltd.