Concentration by evaporation and the prebiotic synthesis of cytosine

Kevin E. Nelson, Michael P. Robertson, Matthew Levy, Stanley L. Miller

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


The efficient prebiotic synthesis of cytosine from urea and cyanoacetaldehyde (CA) has recently been claimed to be invalid on the basis of possible side reactions of the starting materials and the inapplicability of prebiotic syntheses using drying beach conditions. We therefore have investigated the synthesis of cytosine and uracil from urea and cyanoacetaldehyde at 100 °C under dry-down conditions, and in solution at 4 °C and -20 °C. We find that cytosine is produced from the low temperature experiments more efficiently than calculated from the Arrhenius extrapolation from higher temperatures, i.e., 60-120 °C. In addition, we find that CA dimer is as efficient as the monomer in cytosine synthesis. We also studied whether evaporating very dilute solutions of nonvolatile organic compounds will concentrate according to theory. Solutions as dilute as 10-4 M concentrate from pure water approximately according to theory. Similar solutions in 0.5 M NaCl have less than theoretical concentrations due to absorption, but concentrations near dryness were very high.

Original languageEnglish (US)
Pages (from-to)221-229
Number of pages9
JournalOrigins of Life and Evolution of the Biosphere
Issue number3
StatePublished - 2001


  • Cyanoacetaldehyde
  • Cyanoacetaldehyde dimer
  • Cytosine
  • Dry-down conditions
  • Evaporation
  • Prebiotic synthesis
  • Uracil

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Space and Planetary Science


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