高效液相色谱-甲烷动态反应电感耦合等离子体质谱法测定谷物中痕量硒形态

Determination of Trace Selenium Species in Cereals by High Performance Liquid Chromatography-Methane Dynamic Reaction Inductively Coupled Plasma Mass Spectrometry

建立了高效液相色谱-甲烷动态反应电感耦合等离子体质谱联用技术测定谷物中5种硒形态的方法。样品通过蛋白酶XIV恒温振荡萃取,流动相为5 mmol/L、pH=5.0的柠檬酸溶液,用Hamiltion PRP-X100阴离子分析柱,质谱采用甲烷反应模式进行测定。本方法可完全分离5种硒形态,硒代胱氨酸(SeCys2)、甲基硒代半胱氨酸(MeSeCys)、亚硒酸盐(SeⅣ)、硒代蛋氨酸(SeMet)和硒酸盐(Ⅵ)的检测限分别为0.01、0.05、0.05、0.10、0.05μg/L,5种硒形态的线性相关系数均大于0.9999;以黑米样品为基质进行3个浓度水平的加标回收试验,回收率为88.5%~105.0%,测定值的相对标准偏差(n=6)为1.1%~4.4%。采用本方法对市售富硒糙米、黑米和小米等进行了硒形态分析,其有机硒含量占总硒含量的87.5%~92.8%。本方法可以简单、快速、准确地测定谷物中硒的5种形态。

A method for the determination of five selenium species in cereals by high-performance liquid chromatography-methane dynamic reaction inductively coupled plasma mass spectrometry was established.The sample was extracted by protease XIV constant temperature shaking,the mobile phase was 5 mmol/L,pH=5.0 citric acid solution,the Hamilton PRP-X100 anion analysis column was selected,and the mass spectrometry was measured in methane reaction mode.Five selenium forms,i.e.,selenocystine(SeCys2),methylselenocysteine(MeSeCys),selenite(SeIV),selenomethionine(SeMet)and selenate(SeVI)could be completely separated by this method.The detection limits were 0.01,0.05,0.05,0.1 and 0.05μg/L,the linear correlation coefficients of the five selenium species were all greater than 0.9999,The recovery test was conducted by addition of standard solutions to the black rice samples at three concentration levels,giving recoveries ranged from 88.5%to 105.0%,with RSDs(n=6)of the measured values in the range of 1.1%to 4.4%.The prescribed method was used to analyze the selenium species of commercially available selenium-enriched brown rice,black rice and millet,and the organic selenium content accounted for 87.5%~92.8%.This method could simply,quickly and accurately determine the five selenium species in cereals.