ICP-AES测定银条不同部位重金属含量

应用混合酸(HClO4∶HNO3=1∶4)在常压条件下对银条茎叶样品进行消解,采用电感耦合等离子体-原子发射光谱法(ICP-AES)测定了银条不同器官的6种重金属Fe、Zn、Mn、Cu、Cd和Pb含量。校准曲线的相关系数均在0.9998—1.0000之间,加标回收率在97.0%—108.9%之间,相对标准偏差为0.45%—3.20%,实验结果可靠。结果显示,银条叶片和地上茎中的重金属含量顺序均为FeZnMnCuPb、Cd,地下茎中的含量顺序为ZnFeCuMnCdPb;同种重金属元素符合叶片地上茎地下茎的规律(Cu除外),其中Fe元素在叶片中含量分别是地上茎和地下茎的4.11、5.35倍。说明银条地下茎部分是无污染、安全的特色蔬菜。

Determination of Heavy Metals in Different Part of Stachys Floridana by ICP-AES

The stems and leaves of Stachys floridana Schuttl.ex Benth.were digested with the mixture of perchloride acid and nitric acid（1∶4）under the normal pressure,the contents of six heavy metals such as iron,zinc,manganese,copper,cadmium and lead were determined by ICP-AES.The relative coefficients of standard curve were in the range of 0.9998—1.0000,the recoveries were 97.0%—108.9% with RSDs of 0.45%—3.20%.The results showed that the sequence of the content of heavy metals in leaves and aerial stems was as follows：FeZnMnCuPb,Cd.However,the sequence of the content of heavy metals in subterranean stems was as follows：ZnFeCuMnCdPb.The contents of an element order was：leavesaerial stemsubterranean stem,besides Cu,and the content of Fe in leaves was 4.11 times that in aerial stem,5.35 times in subterranean stem.It is concluded that the subterranean stems of Stachys floridana are characteristic vegetables,which are no pollution and safety.