A rapid sample treatment procedure for the gas chromatography-tandem mass spectrometry （GC-MS） determination of 19-nortestosterone （19-NT） in animal tissues has been developed. In our optimized procedures, enzymat...A rapid sample treatment procedure for the gas chromatography-tandem mass spectrometry （GC-MS） determination of 19-nortestosterone （19-NT） in animal tissues has been developed. In our optimized procedures, enzymatic hydrolysis with β-glucuronidase from Escherichia coliwas performed in an acetate buffer （pH 5.2, 0.2 mol/L） Next, the homogenate was mixed with methanol and heated at 60℃ for 15 min, then placed in an ice-bath at -18℃ for 2 h. After liquid-liquid extraction with n-hexane, the analytes were subjected to a normal-phase solid phase ex- traction （SPE） C18 cartridge for clean-up. The dded organic extracts were derivatized with heptafluorobutydc anhydride （HFBA）, and then the products were injected into GC-MS. Using electron impact mass spectrometry （El-MS） with positive chemical ionization （PCI）, four diagnostic ions （mlz 666, 453, 318, and 306） were determined. A standard calibration curve over the concentration range of 1-20 ng/g was reached, with Y=467084X-68354 （R^2=0.9997） for 19-NT, and the detection limit was 0.3 ng. When applied to spiked samples collected from bovine and ovine, the recoveries ranged from 63% to 101% with relative standard deviation （RSD） between 2.7% and 8.9%. The procedure is a highly efficient, sensitive, and more economical method which offers considerable potential to resolve cases of suspected nandrolone doping in husbandry animals.展开更多
基金Project supported by the Eleventh Five-Year Plan for National Science and Technology of China (No.2006BAK02A21/1)the Henan Innovation Project for University Prominent Research Talents (No.2010HASTIT026),China
文摘A rapid sample treatment procedure for the gas chromatography-tandem mass spectrometry （GC-MS） determination of 19-nortestosterone （19-NT） in animal tissues has been developed. In our optimized procedures, enzymatic hydrolysis with β-glucuronidase from Escherichia coliwas performed in an acetate buffer （pH 5.2, 0.2 mol/L） Next, the homogenate was mixed with methanol and heated at 60℃ for 15 min, then placed in an ice-bath at -18℃ for 2 h. After liquid-liquid extraction with n-hexane, the analytes were subjected to a normal-phase solid phase ex- traction （SPE） C18 cartridge for clean-up. The dded organic extracts were derivatized with heptafluorobutydc anhydride （HFBA）, and then the products were injected into GC-MS. Using electron impact mass spectrometry （El-MS） with positive chemical ionization （PCI）, four diagnostic ions （mlz 666, 453, 318, and 306） were determined. A standard calibration curve over the concentration range of 1-20 ng/g was reached, with Y=467084X-68354 （R^2=0.9997） for 19-NT, and the detection limit was 0.3 ng. When applied to spiked samples collected from bovine and ovine, the recoveries ranged from 63% to 101% with relative standard deviation （RSD） between 2.7% and 8.9%. The procedure is a highly efficient, sensitive, and more economical method which offers considerable potential to resolve cases of suspected nandrolone doping in husbandry animals.
