Crystallise anserine from aqueous EtOH. It is hygroscopic and is best stored as the nitrate salt (see below). Purify it by shaking the nitrate salt with Dowex 3 (x4 free base) and washing with H2O, evaporating the filtrate and removing H2O by 3 distillations with 10mL of propan-2-ol. Dissolve the crystals in MeOH and add H2O dropwise until one phase is obtained and cool. Dry the crystals at 60o over P2O5 in a vacuum. The picrate has m 145o (from H2O). [Rinderknecht et al. J Org Chem 29 1968 1964, Beilstein 25 II 408, 25 IV 4383.]