Purification of microcystins by DEAE and C-18 cartridge chromatography

Microcystins (MCs) were purified by DEAE and Cls cartridge chromatography. Addition of EtOH to the eluents (20%) in DEAE chromatography gave higher re solution than no addition of EtOH. The chromatogram showed three peaks: MC- LR; MC-LY and MC-LF; MC-LW. MC-LR and NIC-LW were obtained by one step chro matography with purity of 96 and 88%, respectively. The separation of MC-LF and MC-LW with DEAE chromatography was better than that with reversed-phas e chromatography. MC-LY and MC-LF were separated with C-18 cartridge. On th e chromatogram, there were three peaks consisting of MC-LY (81% purity), MC -LF (86%), and an unknown compound which was considered as a MC variant jud ging from the results in HPLC/PDA, FAB-MS, and H-1 NMR analyses, but the st ructure could not be determined. It is concluded that the combination of DE AE and Cls cartridge chromatography would be a practical approach for the p urification of various MCs. (C) 2001 Elsevier Science Ltd. All rights reser ved.