with either solvent , the order of elution of the compounds is : isoxanthopterin , pterin-6-carboxylic acid , xanthopterin , pterin-6-carboxaldehyde , d-erythro-neopterin , l-threo-neopterin , biopterin , 6-hydroxymethylpterin , pterin , 6-methylpterin .
C0068527
neopterin
C0005562
biopterin