Abstract
Techniques are described for analysis and purification of free and conjugated pteridines by anion-exchange chromatography. The following compounds are adsorbed on Dowex-
i-chloride and eluted with very dilute HCl or with NaCl: biopterin, leucopterin, xanthopterin, PGA, leucovorin, N
10-formyl-PGA, Aminopterin, Amethopterin, Methopterin. During chromatography in the formic acid system, appreciable amounts of PGA are formylated to N
10-formyl-PGA.