Hypoxanthine is the doping component in anhydrous guanine β (AG β) biominerals. In this work, hypoxanthine was doped into all the reported guanine phases by solution methods. N₇-Hypoxanthine was doped into hydrated amorphous guanine (HAmG), anhydrous guanine β form (AG β) and anhydrous guanine α form (AG α) consisting of N₇-guanine, and N₉-hypoxanthine was doped into guanine monohydrate (GM) and dehydrated-GM consisting of N₉-guanine confirmed by FT-IR, Raman, and ss-NMR. We realized the separation of hypoxanthine tautomers in the solid state by using the principle of doping. This strategy would shed light on the solid-state separation of organic molecular tautomers.