[Determination of 12 steroid hormone residues in pig tissues by liquid chromatography-tandem mass spectrometry combining with library search].

A method was developed for the simultaneous determination and identification of 12 steroid hormone residues in pig tissues, including stanolone, aldosterone, boldenone, danazol, metandienone, methyltestosterone, nadrolone, norethindrone, progesterone, stanozolol, testosterone and testosterone propionate, using liquid chromatography-tandem triple-quadrupole linear ion trap mass spectrometry(LC-MS/MS). Homogenized pig tissue samples were purified with a Waters MCX solid phase extraction column after enzymatic hydrolysis by beta-glucuronidase, then separated on a Venusil MP C18 column (100 mm x 2, 1 mm, 3 microm) using gradient elution with the mobile phases of acetonitrile and water with 0.1% (v/v) formic acid. A multiple reaction monitoring (MRM) as survey scan and an enhanced product ion (EPI) scan as dependent scan were performed in an information dependent acquisition (IDA) experiment. The compound identification was carried out by library search with a newly developed MS/MS library based on EPI spectra at three different collision energies in positive mode. The results showed that the limits of detection (LODs, S/N = 3) were in the range of 0.2 - 0.5 microg/kg for the steroid hormones, and with a good linearity (r > 0.99) ranged from 0.5 to 100.0 microg/L. The average recoveries (n = 6) of the 12 steroid hormones spiked in pig tissue samples at 5.0 microg/kg ranged from 72.0% to 98.1% with the relative standard deviations (RSDs) between 3.1% and 12.5%. The method was applied for the qualitative and quantitative determination of steroid hormone residues in pig tissues with sensitive and accurate characteristics.