Dissolve it in CHCl3, wash this with saturated aqueous NaCl, dry (MgSO4), evaporate and purify it by chromatography on silica gel and gradient elution with *C6H6/MeOH followed by preparative reverse phase HPLC on an octadecyl silanised silica (ODS) column and eluting with MeOH. It can be recrystallised from MeOH ( max 1120 cm-1, C-O-C in KBr). [Kimura et al. Anal Chem 59 2331 1987, see also Maruyama et al. J Chem Soc Perkin Trans 1 2069 1986 and Tsukube et al. J Chem Soc Perkin Trans 1 1033 1986.] It complexes selectively with Li ions.
