密闭酸溶-电感耦合等离子体质谱法测定道路扬尘中铜铅锌镉铬镍砷

准确测定道路扬尘样品中重金属元素Cu、Pb、Zn、Cd、Cr、Ni、As,对于城市道路环境污染的防治工作来说意义重大。采用HF-HNO₃体系密闭酸溶法消解样品,选择⁵²Cr、⁶⁰Ni、⁶³Cu、⁶⁶Zn、⁷⁵As、¹¹¹Cd、²⁰⁸Pb为测量同位素,采用He气模式的碰撞反应池技术测定Cr和As,采用仪器自带干扰校正公式对Cd的测定结果进行校正,建立了电感耦合等离子体质谱法(ICP-MS)测定道路扬尘样品中Cu、Pb、Zn、Cd、Cr、Ni、As的方法。重点对溶样条件进行了优化,结果表明,在0.1 g样品中加入7.0 mL由HF和HNO₃按照体积比为1︰6组成的混合酸,于160 ℃密闭溶解2 h可将样品溶解完全。在优化的实验条件下,校准曲线的相关系数均大于0.999,检出限为0.012~0.096 μg/g,定量限为0.040~0.32 μg/g。将实验方法应用于道路扬尘样品中Cu、Pb、Zn、Cd、Cr、Ni、As的测定,并进行加标回收试验,结果的相对标准偏差(RSD,n=12)均小于4%,加标回收率为95%~104%。采用实验方法对道路扬尘样品进行分析,测定结果与高压微波消解-ICP-MS法测定Cu、Pb、Zn、Cd、Cr、Ni,氢化物发生原子荧光光谱法(HG-AFS)测定As的结果基本吻合。

Determination of copper,lead, zinc,cadmium, chromium,nickel and arsenic in road dust by inductively coupled plasma mass spectrometry with acid digestion in closed system

The accurate determination of heavy metals (Cu, Pb, Zn, Cd, Cr, Ni and As) in road dust samples is of great significance for the prevention and control of environmental pollution in urban roads. The samples were digested by acid dissolution in closed system in HF-HNO₃ system. ⁵²Cr, ⁶⁰Ni, ⁶³Cu, ⁶⁶Zn, ⁷⁵As, ¹¹¹Cd and ²⁰⁸Pb were selected as the measuring isotopes. The contents of Cr and As were determined by collision reaction cell technique using mode of He. The determination results of Cd were corrected by the interference correction equation equipped in the instrument. Consequently, the determination method of Cu, Pb, Zn, Cd, Cr, Ni and As in road dust samples by inductively coupled plasma mass spectrometry (ICP-MS) was established. The sample dissolution conditions were optimized. The results showed that 0.1 g of sample could be fully dissolved by 7.0 mL of mixed acid (HF∶HNO₃=1∶6, volume ratio) after digestion in closed system at 160 ℃ for 2 h. Under the optimized experimental conditions, the correlation coefficient of the calibration curve was higher than 0.999. The limit of detection ranged from 0.012 to 0.096 μg/g, and the limit of quantification was between 0.040 μg/g and 0.32 μg/g. The proposed method was applied to the determination of Cu, Pb, Zn, Cd, Cr, Ni and As in road dust samples. Moreover, the spiked recovery tests were also conducted. The relative standard deviations (RSD, n=12) of determination results were all less than 4%, and the spiked recoveries were between 95% and 104%. The road dust samples were analyzed according to the experimental method. The measurement results were basically consistent with those obtained by high-pressure microwave digestion-ICP-MS for Cu, Pb, Zn, Cd, Cr and Ni, and hydride generation atomic fluorescence spectrometry (HG-AFS) for As.