title: [Determination of selenomethionine in selenium-enriched yeast by gas chromatography-mass spectrometry].
abstract: A method has been developed for the determination of selenomethionine in selenium-enriched yeast by gas chromatography-mass spectrometry (GC-MS). Three extraction methods were compared for extraction efficiency of selenomethionine from the samples. Selenomethionine in the samples was extracted for 24 h with proteinase in Tris buffer. The selenomethionine was derivatized with butanol and trifluoroacetic acid (TFA). The derivatization was accomplished in two steps, starting with the esterification of the carboxyl group of the selenoamino acid using butanol, followed by the acylation of the amino group with trifluoroacetic acid anhydride. The selected ion for monitoring selenomethionine was at m/z 349. The instrument operating conditions were optimized. The samples were analyzed by GC-MS with external standard method. Standard GC-MS chromatograms and mass spectra for selenomethionine were also obtained. The method was proved to be accurate and reliable. The recoveries of 98.5%-103.7% with relative standard deviations (RSDs) of 0.9%-2.4% (n = 6) and the correlation coefficient of 0.9978 were obtained. The detection limit of selenomethionine for the method was 0.5 mg/L (S/N = 3) and the selenomethionine contents of real sample was given.
authors.affiliation: College of Veterinary Medicine, Nanjing Agricultural University, China. gsn08@yahoo.com.cn
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Gao
authors.forename: Kehe
authors.initials: K
authors.lastname: Huang
authors.forename: Shunyi
authors.initials: S
authors.lastname: Qin
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D037742:Nanotubes, Carbon / Q000737:chemistry; D012645:Selenomethionine / Q000032:analysis*; D015002:Yeast, Dried / Q000032:analysis*
chemical_list: D037742:Nanotubes, Carbon; D012645:Selenomethionine