Development and validation of a LC-MS/MS method for the determination of isoeugenol in finfish

A simple, rapid, selective and sensitive LC-MS/MS method was developed and validated for the determination of isoeugenol in finfish using an off-line dansylation derivatization step to enhance signal intensity. The sample was extracted with 10mL acetone using a tissue homogenizer, followed by derivatization with dansyl chloride and analysis by liquid chromatography tandem mass spectrometry. The method detection limit ranged from 0.2 to 0.7ngg^-1 in six fish species. The limit of quantification was 2.5ngg^-1 in each species. Recoveries of isoeugenol at three different levels (5, 10 and 20ngg^-1) over two different days ranged from 91.2% to 108.0%. Precision (%RSD_R) values determined at 10ngg^-1 were 4.3%, 8.0%, 5.3%, 5.1%, 2.6% and 8.0% for tilapia, catfish, trout, salmon, hybrid striped bass and yellow perch, respectively. Studies of linearity in the range 2.5-40ngg^-1 produced determination coefficients (R²) above 0.997 for all matrices.