LABORATORY-SCALE PURIFICATION OF MICROCYSTINS USING FLASH CHROMATOGRAPHY AND REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Microcystins were extracted from 71 (equivalent to 313 g dry weight) o f cyanobacterial scum collected from Rutland Water in Leicestershire, UK in 1989. The resulting aqueous extract was rapidly concentrated on a C-18 flash chromatography cartridge and microcystins were eluted usi ng a step gradient. Fractions were collected manually and monitored by UV spectrophotometer and analytical HPLC. Fractions containing microc ystins of similar polarity were pooled to give three fractions. Simple isocratic methods for separating each fraction were developed on an a nalytical column and scaled up to a 15X7.5 cm I.D. column. Closed-loop recycling was used to maximise yield and purity of two hydrophobic mi crocystins.