Determination of residues of tricaine in fish using liquid chromatography tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC–MS/MS) method for the determination of residues of the anaesthetic tricaine mesilate (MS222) in fish tissues is described. Residues were extracted from homogenized tissues with McIllvaine buffer/methanol and purified over a C18 solid-phase extraction column followed by LC–MS/MS analysis. In the multiple-reaction monitoring mode of the mass spectrometer, chromatograms were recorded by monitoring the m/z 166 → m/z 138 and m/z 166 → m/z 94 transitions for quantification and confirmation of the residues in the finfish matrix, respectively. Recoveries were in the range of 67% ± 10% (n = 6) for tilapia at 2 μg kg−1, 95% ± 7% (n = 6) at 2 μg kg−1 in salmon and 92% ± 3% (n = 5) for trout at 2.5 μg kg−1. The limits of detection were 0.5, 0.6 and 0.6 μg kg−1 in trout, salmon and tilapia, respectively. No residues of tricaine were found in eight sampled aquacultured fish (salmon and trout) bought from the local market.