全自动石墨消解–电感耦合等离子体质谱法测定农用地土壤中7种金属元素

Determination of 7 Metal Elements in Agricultural Soil by Automatic Graphite Digestion-Inductively Coupled Plasma Mass Spectrometry

  • 摘要: 建立全自动石墨消解–电感耦合等离子体质谱(ICP-MS)法测定土壤中Cd、As、Pb、Cr、Cu、Ni、Zn 7种元素. 采用8 mL HNO3+5 mL HCl+5 mL HF+1 mL HClO4酸体系消解3 h,设定160 ℃赶酸温度,以Rh-Re为内标定量,电感耦合等离子体质谱仪选取碰撞模式测定土壤样品. 结果显示:7种不同元素在一定线性范围内相关性良好,相关系数均大于0.999,检出限为0.02~0.5 mg/kg,定量限为0.08~2.0 mg/kg. 土壤有证标准物质测定结果的相对标准偏差为0.9%~6.1%,相对误差为−8.9%~7.6%. 水稻田、果园、人工草地3种典型农用地土壤样品中7种元素加标回收率分别为85.4%~109.0%、86.4%~102.0%、85.8%~99.0%. 方法的检出限低、精密度和正确度高,满足农用地土壤污染状况详查质量保证与质量控制的技术规定.

     

    Abstract: An automatic graphite digestion-inductively coupled plasma mass spectrometry (ICP-MS) has been established for the determination of 7 elements, Cd, As, Pb, Cr, Cu, Ni and Zn in soil. The soil samples were digested with 8 mL HNO3+5 mL HCl+5 mL HF+1 mL HClO4 system for 3 h, with a acid driving temperature of 160 ℃. After digestion, the soil samples were quantified by Rh-Re as the internal standard and determined using the collision mode of inductively coupled plasma mass spectrometer. The results showed that the 7 elements had good correlation within a certain linear range, with correlation coefficients all greater than 0.999. The limits of detection were 0.02~0.5 mg/kg, and the limits of quantitation were 0.08~2.0 mg/kg. The relative standard deviation of the determination results of certified reference materials in soil was 0.9%~6.1%, and the relative error was −8.9%~7.6%. The spiked recoveries of the 7 elements in three typical agricultural soils, namely paddy fields, orchards, and artificial grasslands, were 85.4%~109.0%, 86.4%~102.0%, and 85.8%~99.0%, respectively. The method has a low detection limit, high precision and accuracy, and can meet the technical requirements for quality assurance and quality control of detailed investigation of pollution in agricultural soil.

     

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