during 30 min on an Agitelec overhead shaker.The sample extract was centrifuged and a phase separation was induced by adding 5 mL of a 0.2 M ammonium bicarbonate buffer pH 10 and 5 mL of a saturated solution of ammonium sulphate to 15 mL of the extract. 5 mL of the ethyl acetate phase was evaporated until dryness, and the residue was reconstituted in 200 μL of methanol/acetonitrile/water (20/40/40, v/v/v).