[Determination of three estrogens in animal liver and kidney tissues by liquid chromatography-tandem mass spectrometry].

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of estrone, 17beta-estradiol, estriol in animal liver and kidney tissues. The sample was extracted by tert-butyl methyl ether, and the extract was evaporated by nitrogen at 45 degrees C. The residue was redissolved in hexane-dichloromethane (6:4, v/v), then purified on a silica solid-phase extraction column. The eluant was evaporated by nitrogen, dissolved in acetonitrile-water (7:3, v/v) and then analyzed by LC-MS/MS. The separation of estrogens was performed on a Poroshell 120 EC-C18 column with the mobile phases of acetonitrile and water with a gradient elution. The identification and quantification of estrogens were carried out by negative electrospray ionization in the multiple reaction monitoring mode using external standard method. The calibration curves showed good linearity in the range of 1.0-20.0 microg/kg with the correlation coefficients above 0.99. The limit of quantification was 1.0 microg/kg for each estrogen. The average recoveries of the estrogens spiked at 1.0, 2.0, 10.0 microg/kg levels in different matrices were between 70.2% and 114%, and the relative standard deviations were between 2.01% and 14.5%. The method is simple, rapid, sensitive, good in purification effect. It is suitable for the confirmation and quantification of estrogens in animal liver and kidney tissues.