Determination of Selenoamino Acids in Selenium-Enriched Soybeans by High Performance Liquid Chromatography-Hydride Generation Atomic Fluorescence Spectrometry
0.1 g of defatted selenium-enriched soybean sample was taken into a centrifuge tube,and the sample was ultrasonicated with 5 mL of 130 mmol·L-1 tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution at pH 7.5 for 30 min,then enzymatically hydrolyzed with 15 mg of pronase for 5 h at 37℃,and centrifuged to take the supernatant,which was passed through 0.22 μm nylon organic filter membrane.Selenocysteine(SeCys),selenomethionine(SeMet),and methylselenocysteine(MeSeCys)in the filtrate were separated on Agela MP-C18 column,and eluted isocratically with 40 mmol·L-1 ammonium hydrogen phosphate solution(pH 7.0)containing 2%(volume fraction)methanol and 0.5 mmol·L-1 tetrabutylammonium bromide.The three selenoamino acids were determined by hydride generation atomic fluorescence spectrometry.As shown by the results,the baseline separation of the three selenoamino acids could be achieved within 7 min,and the linear ranges of the standard curves were all 5-100 μg·L-1,with detection limits of 0.086,0.075,and 0.047 mg·kg-1 respectively.The recoveries of the three selenoamino acids according to the standard addition method were in the range of 85.5%-103%,and RSDs of the determined values(n=7)were not greater than 3.0%.This method was applied to analysis of the selenoamino acids in selenium-enriched soybeans,and the selenium fugitive form in soybeans was mostly SeMet,which accounted for 85.5%-94.5%of the total selenium.
high performance liquid chromatography-hydride generation atomic fluorescence spectrometry(HPLC-HG-AFS)seleniumsoybeanselenoamino acidform of selenium
NETL
NSTL
万方数据
