Key Laboratory of Analysis and Detection for Food Safety of Ministry of Education, Fujian Provincial Key Lab of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
Talanta. 2011 May 15;84(3):983-8. doi: 10.1016/j.talanta.2011.03.004. Epub 2011 Mar 8.
An enzyme-assisted extraction used to extract all species of selenium in rice sample and a sensitive analytical method for the determination of ultratrace Se(VI), Se(IV), SeCys(2) (selenocystine) and SeMet (selenomethionine) with capillary electrophoresis-inductively coupled plasma mass spectrometry were firstly described in this study. The extraction method is simple, effective and can be used to extract trace selenium compounds in rice with high extraction efficiency and no altering its species. The analytical method has a detection limit of 0.1-0.9 ng Se/mL, and can be used to determine trace Se(VI), Se(IV), SeCys(2) and SeMet in rice directly without any derivatization and pre-concentration. With the help of above methods, we have successfully determined Se(VI), Se(IV), SeCys(2) and SeMet in selenium-enriched rice within 18 min with a recovery of 90-103% and a RSD (relative standard deviation, n=6) of 3-7%. Our results indicated that selenium-enriched rice contained only one species of selenium, SeMet, and its concentration is in range of 0.136-0.143 μg Se/g dried weight. The proposed method providing a realistic approach for the nutritional and toxical evaluation of different selenium compounds in nutritional supplements.
本研究首次描述了一种酶辅助提取方法，用于提取水稻样品中的所有硒物种，以及一种用于测定痕量硒（VI）、硒（IV）、硒半胱氨酸（2）（硒代胱氨酸）和硒代蛋氨酸（硒代蛋氨酸）的灵敏分析方法，采用毛细管电泳-电感耦合等离子体质谱法。该提取方法简单、有效，可用于高效提取水稻中痕量硒化合物，且不改变其形态。该分析方法的检测限为 0.1-0.9 ng Se/mL，可直接用于测定水稻中的痕量硒（VI）、硒（IV）、硒半胱氨酸（2）和硒代蛋氨酸，无需衍生化和预浓缩。借助上述方法，我们成功地在 18 分钟内测定了富硒大米中的硒（VI）、硒（IV）、硒半胱氨酸（2）和硒代蛋氨酸，回收率为 90-103%，相对标准偏差（n=6）为 3-7%。我们的结果表明，富硒大米中仅含有一种硒物种，即硒代蛋氨酸，其浓度范围为 0.136-0.143μg Se/g 干重。该方法为营养补充剂中不同硒化合物的营养和毒性评价提供了一种现实的方法。
