Degradation of uric acid and 3-ribosyluric acid during treatment with charcoal

Uric acid and 3-ribosyluric acid at a concentration of 1.5 × 10^?4M were quantitatively adsorbed to charcoal, but were not recovered when the charcoal was washed with ethanol:water:NH₄OH (60:36:4), a solvent which readily eluted a number of other bases and nucleosides. With 2-¹⁴C]uric acid it was shown that the radioactivity was adsorbed to the charcoal and that ¹⁴C]allantoin was the primary product recovered after elution. Incubation of uric acid or 3-ribosyluric acid in the ethanol:water:NH₄OH did not result in any degradation. The elution of uric acid from charcoal with other eluents such as 7% phenol, 0.1 M NaOH, or ethanol:water:pyridine (50:40:10) also resulted in the conversion of uric acid to allantoin. It was concluded that when uric acid and 3-ribosyluric acid are adsorbed to charcoal and then eluted, there is a substantial conversion of these compounds to the corresponding allantoin.