研究建立了四级杆碰撞反应池-ICP-MS法(Inductively coupled plasma mass spectrometry,ICP-MS)测定维生素及其预混料中铅、总砷和总汞的检测方法.样品加入硝酸,经微波消解后定容至100 mL,待测液采用四级杆碰撞反应池-ICP-MS法进行测定.由于汞易挥发,实验中优化了消解的温度.维生素B12样品中存在钴元素的干扰,以75砷(As)和内标元素73锗(Ge)的信号强度比值与砷元素的浓度成正比,采用碰撞反应池技术、氦气动能歧视(Kinetic energy discrimination,KED)模式进行定量分析,计算结果为样品中As和Co-O结合物的总含量;再以59钴(Co)和内标元素45钪(Sc)的信号强度比值与钴元素的浓度成正比,采用同样方法进行定量分析,得出钴的含量.最后通过计算两者之差得出样品中砷的含量.试验结果表明:铅、总砷和钴在1.0～50.0 μg/L范围内线性关系良好,相关系数R均大于0.999.在不同加标水平下,3种元素的回收率范围在88.3％～104.3％之间,汞在0.1～2.0 μg/L范围内线性关系良好,相关系数R为0.998.在不同加标水平下,汞元素的回收率范围在88.3％～104.3％之间,相对标准偏差(RSD)均小于10％.该方法操作简便、快速准确,适用于维生素及其预混料中铅、总砷、总汞元素的同时检测.
Study on the quantitative analysis of lead,arsenic and mercury in vitamin by quadrupole collision reaction Cell-ICP-MS
The determination of lead,total arsenic and total mercury in vitamin by quadrupole collision reaction cell-ICP-MS was established.The samples were soluted by using HNO3 with microwave digestion,and then added water to 100 mL.The solution was determined by ICP-MS with KED mode.the pre-digestion temperture was optimized because mercury is highly volatile element.Because of the interference by cobalt,75As was used for quantitative analysis for total arsenic and Co-O combination while 73Ge was used as internal standard,then 59Co was used for quantitative analysis while 45Sc was used as internal standard.The D-value between them was the content of total arsenic.The concentration of lead,arsenic and cobalt standard solution showed a good linear relationship in the range of 1.0-50.0 μg/L,and the correlation coefficient was all above 0.999.The recoveries for the three elements were in the range of 88.3％-104.3％at the three spiked levels,The concentration of mercury standard solu-tion showed a good linear relationship in the range of 0.1-2.0 μg/L,and the correlation coefficient was 0.998.The recoveries for mercury was in the range of88.3％-104.3％at the three spiked levels,with relative standard deviations(RSD)less than 10％.The method was simple,rapid and accurate,which was suitable for the quantitative detection of lead,total arsenic and total mercury in vitamin.
vitamininductively coupled plasma mass spectrometrykinetic energy discriminationtotal arsenictotal mercurycobalt
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