摘要
[目的]应用高效液相—电感耦合等离子体质谱法(HPLC-ICP-MS)建立一种同时测定食品中亚砷酸根[As(Ⅲ)]、砷酸根[As(V)]、一甲基砷酸(MMA)、二甲基砷酸(DMA)、砷甜菜碱(AsB)、甲基-硒代半胱氨酸(MeSeCys)、硒代蛋氨酸(SeMet)、硒代胱氨酸(SeCys2)、亚硒酸根[Se(Ⅳ)]、硒酸根[Se(Ⅵ)]共10种砷、硒元素形态的分析方法.[方法]以富硒大米为研究对象,通过比较不同的提取方式,不同种类酶的提取效果,确定最佳提取方法.同时比较不同色谱柱、不同流动相组成、不同流动相pH、不同流动相流量、不同流动相中甲醇含量、不同柱温下10种砷硒元素形态的分离效果,确定最佳的提取条件和分离条件.[结果]最佳的分离条件为采用Aglient ZORBAX SB-Aq色谱柱,用pH值分别为4.0和6.0的20 mmol/L柠檬酸+5 mmol/L己烷磺酸钠+4％甲醇为流动相梯度洗脱,流量为1.0 mL/min,电感耦合等离子体质谱(ICP-MS)采用HEHe模式检测.最佳提取条件为Tris-HCl(pH 7.5)缓冲溶液添加15 mg蛋白酶K和15 mg蛋白酶E.该方法可在5 min内完全分离出10种不同的砷硒元素形态,在0～50 μg/L范围内,各元素形态线性关系良好,相关系数均大于0.999 5,其中As(Ⅴ)、MMA、As(Ⅲ)、DMA、AsB、Se(Ⅵ)、Se(Ⅳ)、SeCys2、MeSeCys 和 SeMet 的检出限分别为 0.10,0.10,0.12,0.14,0.22,0.15,0.15,0.18,0.12,0.15 μg/L.加标回收率范围为76.0％～104.2％,相对标准偏差为1.1％～8.5％.[结论]该方法操作简便、快速、灵敏度高且完全满足富硒食品中砷、硒形态的准确定量分析.
Abstract
[Objective]A method for the simultaneous determination of arsenate[As(Ⅲ)],Arsenate[As(Ⅴ)],monomethylarsenate(MMA),dimethylarsenate(DMA),Arsine betaine(AsB),methyl-selenocysteine(MeSeCys)and selenomide in food was developed by high performance liquid phase inductively coupled plasma mass spectrometry(HPLC-ICP-MS),and a total of 10 kinds of arsenic and selenium element forms of As and Se,including acid(SeMet),selenocysteine(SeCys2),selenite[Se(Ⅳ)]and selenate[SE(Ⅵ)].[Methods]Taking selenium rich rice as the research object,the best extraction method was determined by comparing different extraction methods and different kinds of enzymes.Moreover,different chromatographic columns,mobile phase composition,mobile phase pH,mobile phase flow,mobile phase methanol content and column temperature were compared to determine the best extraction and separation conditions.[Results]The optimal separation conditions were using Aglient ZORBAX SB-Aq chromatographic column with 20 mmol/L citric acid+5 mmol/L sodium hexane sulfonate+4％methanol as the mobile phase gradient with pH values of 4.0 and 6.0 respectively.Elution was performed at a flow rate of 1.0 mL/min,and inductively coupled plasma mass spectrometry(ICP-MS)was detected using HEHe mode.The optimal extraction condition is Tris-HCl(pH 7.5)buffer solution adding 15 mg proteinase K and 15 mg proteinase E.This method can completely separate 10 different forms of arsenic and selenium within 5 minutes.In the range of 0～50 μg/L,the linear relationship between the forms of each element is good,and the correlation coefficient R＞0.999 5.The detection limits of As(V),MM A,As(Ⅲ),DMA,AsB,Se(Ⅵ),Se(Ⅳ),SeCys2,MeSeCys and SeMet are 0.10,0.10,0.12,0.14,0.22,0.15,0.15,0.18,0.12,0.15 μg/L respectively.The spiked recovery rate ranged from 76.0％to 104.2％,and the relative standard deviation ranged from 1.1％to 8.5％.[Conclusion]This method is simple,fast,highly sensitive and fully meets the requirements for accurate quantitative analysis of arsenic and selenium speciation in selenium-rich foods.
基金项目
湖北省重点研发计划项目(2022BBA0077)
湖北省市场监督管理局科技计划专项项目(Hbscjg-KJ2023005)
国家科技期刊平台
NSTL
万方数据