Abstract: A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the simultaneous determination of background values of 4 hormones (testosterone, methyltestosterone, progesterone and hydrocortisone) in milk and chicken. The samples were hydrolyzed by β-glucuronidase and ultrasonically extracted with acetonitrile, and then the extract was defatted with hexane. The analytes were seperated on a ZORBAX SB-C18 column with methanol-0.1% formic acid as mobile phase by gradient elution. The mass spectrometer was run in multiple reaction monitoring mode (MRM) using positive- and negative-ion electrospray ionization (ESI), respectively. The quantitative analysis was carried out by matrix-matched external standard method. The results showed that the calibration curves had good linearity for 4 hormones in the tested concentration ranges, with correlation coefficients of more than 0.991. The limits of detection (LOD, RSN = 3) and limits of quantitation (LOQ, RSN = 10) were 0.02–0.10 and 0.06–0.33 μg/kg in milk, and 0.03–0.12 μg/kg and 0.10–0.40 μg/kg in chicken, respectively. The average recoveries at three spiked levels 56.0%–132.8% for milk and 79.6%–122.0% for chicken, and the precisions expressed as relative standard deviations (RSDs) were 1.8%–17.3% for milk and 2.0%–18.1% for chicken. The method proved to be simple, rapid, accurate, and suitable for rapid screening and detection of background values for 4 hormones in milk and chicken.

Key words: hormones, chicken, milk, background values, high performance liquid chromatography-tandem mass spectrometry