Aliquots of 0.2 g (liver) or 0.5 g (hepatopancreas) of sample
were transferred to a mortar (30 mL capacity), spiked with the
standard solution and, after solvent evaporation (approximately
one hour), gently homogenized with a pestle with 1 g reused C18
for 5 min to obtain a homogeneous mixture. The mixture was
poured into a 15 mL centrifuge polypropylene tube; 5 mL acetonitrile
was added and the content was thoroughly vortexed for
1 min. Then, the tubes were placed into a centrifuge at 4000 rpm
for 10 min. The extract was collected and 2 mL was injected into
the GC–MS