目的:建立电感耦合等离子体质谱法(inductively coupled plasma mass spectrometry,ICP-MS)测定芜青种12种金属元素含量的分析方法.方法:采用微波消解法以硝酸为消解体系,对样品进行前处理,以Re、In、Rh、Ge为混合内标溶液测定Mg,Ca,Fe,Zn,Sr,Mn,Cu,Cr,Cd,Hg,Pb,As.采用电感耦合等离子体质谱法,对12种金属元素的含量进行测定.结果:各金属元素在各自的浓度范围内线性关系良好相关系数均>0.999,方法检出限为 0.007~1.069 μg/L,对芜青实际样品进行测定,各元素的相对标准偏差(RSD,n=6)在0.378%~3.035%,加标回收率为96%~137%;测定六批不同产地的芜青样品,使用多变量分析评估所得数据,主成分分析(PCA)显示 6批样品主成分载荷提取的3个成分约占总方差的86.993%.聚类分析(CA)显示存在三个金属基团,第一组为Mg,第二组为Ca,第三组为Fe、Zn、Sr、Mn、Cu、Cr、Cd、Hg、Pb和As.PCA与CA结果的相关性较好.结论:该方法操作简便、分析快速、灵敏度高、结果准确、适用于芜青中金属元素含量的测定.
Determination of 12 Metal Elements in Brassica Rapa L.by Inductively Coupled Plasma-mass Spectrometry and Multivariate Analysis
Objective:To establish a method for determination of 12metal elements in Brassica rapa by inductively coupled plasma mass spectrometry(ICP-MS).Methods:The samples were pretreated with nitric acid as the digestion system by microwave digestion,and Mg,Ca,Fe,Zn,Sr,Mn,Cu,Cr,Cd,Hg,Pb and As were determined by inductively coupled plasma mass spectrometry.Results:The linear relationship of each metal element was good in each concentration range,R2>0.999 and the detection limits of the method were 0.007~1.069 μg/L.The relative standard deviations(RSD,n=6)of the elements were in the range of 0.378%~3.035%for the determination of the actual samples of Brassica rapa.The spiked recoveries ranged from 96%to 137%;six batches of Brassica rapa samples of different origins were measured and the data obtained were evaluated using multivariate analysis,and principal component analysis(PCA)showed that the three components extracted from the principal component loadings of the six batches accounted for about 86.993%of the total variance.Cluster analysis(CA)showed the presence of three metal groups,Mg in the first group,Ca in the second group,and Fe,Zn,Sr,Mn,Cu,Cr,Cd,Hg,Pb,and As in the third group.the correlation between the PCA and CA results better characterized the homogeneity of the quality of this Brassica rapa sample batch.Conclusion:This method provides quick response,high sensitivity,and reliable testing results,which is suitable for the determination of metal elements in Brassica rapa.