Interactions of Thymine and Uracil with Copper, Cobalt and Silver Ferrocyanides and the Implications in Chemical Evolution

Effects on pH based adsorption of nucleic acid bases (thymine and uracil) at two different concentrations 1 x 10-4 M and 1 x 10-5 M on copper, cobalt and silver ferrocyanides were studied over a pH range (1.0 – 10.0) at temperature 30±1ºC. The progress of adsorption was followed spectrophotometrically by measuring the UV absorbance of the nucleic acid base solutions at their corresponding max. Maximum adsorptions were found at neutral pH for both thymine and uracil. Effects of concentrations on adsorption of thymine and uracil on copper, cobalt and silver ferrocyanides were studied in a concentration range 10-4 – 10-5 M at neutral pH 7.0 ± 0.1 and at temperature 30±1°C. The interaction followed the Langmuir type of adsorption in general in the concentration range of 10-4 to 10-5 M of thymine and uracil solution. The uptake of nucleic bases on metal ferrocyanides followed the order of CuFc > AgFc > CoFc for the adsorption of thymine and CuFc > CoFc > AgFc for the adsorption of uracil. Effects of the presence of salts on the adsorption of thymine and uracil on metal ferrocyanides also had been studied. The insoluble metal ferrocyanides’ interaction with biomolecules must have either formed metal complexes or could have enhanced the formation of biopolymers in fluctuating environment.