Abstract: A rapid, specific and highly sensitive method for the determination of seven sex hormones (norgestrel, methyltestosterone, testosterone propionate, medroxyprogesterone acetate, megestrol acetate, chlormadinone acetate, and nandrolone) residues in fish products was developed using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with electrospray ionization (ESI) in positive mode. The target compounds were extracted with methanol after the enzyme hydrolysis of the fish products. ZnCl2 was added to the extract solution to remove lipids. Then target compounds were purified by an LC-C18 and an LC-NH2 solid phase extraction cartridges. The target compounds were separated on a Waters ACQUITYTM UPLC BEH-C18 column (100 mm×2.1 mm, 1.7 μm) and detected qualitatively and quantitatively in multi reaction monitoring (MRM) mode. For the seven sex hormones, the limits of detection (LOD) of the method were from 0.08 to 0.17 μg/kg and the limits of quantification (LOQ) were in the range of 0.24~0.58 μg/kg. At the spiked levels of 1 and 4 μg/kg, the average recoveries ranged from 76% to 118% with the relative standard deviations between 5.0% and 11.3% for the seven sex hormones using internal standard method; and the average recoveries ranged from 66% to 94% with the relative standard deviations between 4.5% and 10.7% using matrix matched external standard method. The results showed that both methods are able to meet the multi-residue detection of the seven sex hormone residues in fish products. The degreased large yellow croaker and roast fish fillet real samples from a local market were detected by the developed method, and the seven targets were not found.

Key words: fish products, multi-residues, sex hormones, ZnCl2 delipidation , ultra performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS)