After adding 50mLof 10% NaCl solution, exhaustive liquid–liquid extraction (three times) was done to transfer analytes to a petroleum ether phase which was evaporated at 35 ◦C
in a rotary evaporator system (composed by a vacuum controller V-850, a rotavapor R-210, a heating bath B-491 and a vacuum pump V-700 from Büchi GmbH, Switzerland, and a minichiller,from Huber GmbH, Germany), releasing the vacuum with nitrogen flow.