Determination of steroid hormone residues in farmed fish using high-resolution orbital ion trap mass spectrometry.

Abstract

A method for the determination of 15 steroid hormones in farmed fish by liquid chromatography-orbital ion trap mass spectrometry has been developed and validated. The method involved sample preparation with acetonitrile extraction and clean-up, and separation in the LC using a C18 column. The orbital ion trap MS was operated at a resolution of 35 000 FWHM in selected ion monitoring mode. An ion source with heated electrospray ionization was used in positive ionization mode. The samples were prepared by solid-phase extraction. The limit of quantification of steroid hormones in fish samples was 2 μg kg-1. Good linearity was observed since correlation coefficients were more than 0.99 for all compounds. Recoveries of spiked fish samples (2 μg kg-1 and 20 μg kg-1) ranged from 80.8% to 112.6% with relative deviations less than 15%. The method was successfully applied to detect steroid hormones in real farmed fish samples at the μg kg-1 level.