The strain Microcystis aeruginosa LEGE 91341 was grown for 20 days in 50 mL of Z8 medium, at 25 °C, under a 14h/10h light (10-30 μmol photons s -1 m -2 )/dark cycle. Biomass from stationary-phase was harvested by centrifugation (5000 ×g, 10 min, 4 °C, Gyrozen 2236R) and frozen. For small scale extraction, 30 mg of the frozen biomass was homogenized using liquid nitrogen and extracted using methanol (2 × 20 mL) at room temperature with shaking. The supernatant was obtained by centrifugation and the solvent was evaporated in a rotary evaporator. The resulting extract was weighted and ressuspended in MeOH (1 mg mL -1 ) and filtered through a 0.2 μm regenerated cellulose syringe filter. Ten microliters (10 µL) of the extract were injected into the LC-HRESIMS system fitted with an ACE Ul-traCore 2.5 Super C18 (75 mm × 2.1 mm) column. Samples were eluted at 0.35 mL min -1 using a linear gradient from 99.5% solution A (95% H2O, 5% MeOH, 0.1% HCOOH v/v) and 0.5% solution B (95% isopropanol, 5%