Determination of microcystins in cyanobacterial samples using microliquid chromatography

A method using microliquid chromatography followed by ultraviolet detection (micro LC/UV) has been developed for the analysis of potent cyanobacterial toxins known as microcystins. The technique, which uses a 0.32-mm i.d. column, enables the detection of 10 pg of microcystins-YR and -LR and 50 pg of microcystin-RR. These values correspond to direct injection of 200 nL of 50- and 250-mu g/L solutions, respectively. The coupling of microchromatography with ion-spray and mass spectrometry has also been preliminarily examined. A detection limit of 1 mg/L can be reached for microcystin-LR. The production of toxins by three strains of Cyanobacteria, namely Microcystis aeruginosa PCC7806, M. aeruginosa PCC7813, and Oscillatoria agardhii PCC7805 has been evaluated by micro LC/UV. Microcystin-LR was present in the cellular materials at concentrations of 42, 17, and 6 mu g/g dried weight, respectively. (C) 1997 John Wiley & Sons, Inc