Simultaneous determination of pharmaceuticals and metabolites in fish tissue by QuEChERS extraction and UHPLC...

In recent years, the occurrence, fate, and adverse effects of pharmaceutically active compounds (PhACs) in aquatic organisms have become a noteworthy issue. In the present study, a rapid and sensitive multiresidue analytical method was developed for the determination of 18 parent PhACs and 5 metabolites in sea bream (Sparus aurata), by combining a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) procedure with ultra-high performance liquid chromatography-Orbitrap-mass spectrometry (UHPLC-Orbitrap-MS). The method development involved optimization of extraction solvent, extraction salts, clean-up sorbents, and amount of sample evaluation, while identification on Orbitrap MS was based on accurate mass and further confirmation with MS/MS fragmentation. The developed method was validated, and linearity was higher than 0.99. Recoveries in all cases ranged between 62 and 107% (at 10, 50, and 100 ng g^-1), while intra-day and inter-day precision, expressed as relative standard deviation, RSD, was lower than 4% and 7%, respectively. In addition, limits of quantification (LOQs) ranged between 0.5 and 19 ng g^-1. The compounds presented a low matrix effect, between - 13 and 4%, while the expanded uncertainty U% estimated at the three spiking levels 10, 50, and 100 ng g^-1 was found below 49% in all cases. Finally, the validated method was applied to sea bream samples from an aquaculture farm located in the Mediterranean Sea, with one positive finding for the antibiotic trimethoprim at a concentration of 26 ng g^-1, presenting negligible human health risk.