原子吸收光谱法测定烟叶中的重金属总量及形态分析

Determination of Total Amount of Heavy Metals by Atomic Absorption Spectrometry and Their Speciation Analysis in Tobacco

采用火焰原子吸收光谱法测定烟叶中Mn,Cu,Zn元素,石墨炉原子吸收光谱法测定Cd,Cr,Pb元素,以HNO3-H2O2微波消解法获取烟叶中的重金属总量,以超声水提取法获取水溶态重金属进行初级形态分析,以Tessier逐级提取法获取5种形态的重金属进行次级形态分析。实验结果表明,原子吸收光谱法检测6种重金属线性良好,相关系数（r^2）不低于0.998 8,检出限为0.16-3.1μg·L^-1。烟叶样品中Mn,Cu,Zn,Cd元素主要以可交换态和碳酸盐结合态的形式存在;Cr主要以残渣态的形式存在;而Pb主要以碳酸盐结合态和残渣态的形式存在。

Mn,Cu,Zn in tobacco were detected by flame atomic absorption spectrometry,and Cd,Cr,Pb were detected by graphite furance atomic absorption spectroscopy.The method of HNO3-H2O2 microwave digestion was used to obtain total amount of heavy metals.The water soluble speciation of heavy metals were gained by ultrasonic water extraction method for primary speciation analysis,and five species of heavy metals were acquired by Tessier step by step extraction method for the second speciation analysis.The results showed that the linearity was good in detection of six kinds of heavy metals by atomic absorption spectrometry,and the correlation coefficients were not less than 0.998 8 with detection limits of 0.16-3.1 μg·L^-1.Mn,Cu,Zn and Cd elements in tobacco were mainly in the form of exchangeable speciation and carbonate bounded speciation while Cr was mainly in residual speciation and Pb was mainly in carbonate bounded speciation and residual speciation.