全自动除盐分离富集系统串联电感耦合等离子体质谱(ICP-MS)法测定食盐中7种重金属含量

Determination of 7 Kinds of Heavy Metals in Table Salt by Inductively Coupled Plasma Mass Spectrometry(ICP-MS)with Automatic Desalt Separation and Enrichment System

为了实现食盐中重金属元素的绿色分离和快速检测,建立了全自动除盐分离富集系统串联电感耦合等离子体质谱(ICP-MS)法测定食盐中7种重金属含量的方法。食盐样品经微波消解后通过全自动除盐分离富集系统使食盐中的Cd、Cu、Co、Ni、Mn、Pb、Zn金属离子与亚氨二乙酸基团和乙二胺四乙酸基团混合树脂形成螯合物,经固相萃取、洗脱,实现金属离子从食盐样液中定量分离富集,最后将样液泵入ICP-MS仪进行检测。结果表明,在最佳实验条件下,所测7种重金属在0.5~15μg/L浓度范围内线性关系良好,相关系数R 2均大于0.999,检出限为0.0006~0.045 mg/kg,3个浓度水平的加标回收率为89.0%~111%,相对标准偏差(RSD)在0.81%~4.6%。采用全自动除盐分离富集系统串联电感耦合等离子体质谱(ICP-MS)法实现了食盐中重金属的绿色前处理,方法具有灵敏度高、重复性好、结果准确的优点,适用于食盐中金属的测定。

In order to realize green separation and rapid detection of heavy metals in table salt,a method for the determination of seven heavy metals in table salt by inductively coupled plasma mass spectrometry(ICP-MS)with automatic desalt separation and enrichment system was established.After microwave digestion of table salt samples,the automatic desalt separation and enrichment system was used to form chelates by mixing Cd,Cu,Co,Ni,Mn,Pb,Zn metal ions in table salt with resin of iminodiacetic acid group and ethylenediamine tetraacetic acid group.Then,the quantitative separation and enrichment of metal ions from table salt sample solution was realized after solid phase extraction and elution.Finally,the sample liquid was pumped into ICP-MS for detection.The results showed that the linear relationships of the seven heavy metals measured by this method were good in the concentration range of 0.5-15μg/L under the optimal experimental conditions.The corresponding correlation coefficients R 2 were all greater than 0.999,the detection limits were 0.0006-0.045 mg/kg,the recoveries of the three concentrations ranged from 89.0%to 111%,and the RSD ranged from 0.81%to 4.6%.The green pretreatment of heavy metals in table salt was realized by using the automatic desalt separation and enrichment system coupled with ICP-MS.The method has the advantages of high sensitivity,good repeatability and accuracy,and is suitable for the determination of metals in table salt.