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目的通过对微波消解中不同酸体系的筛选和相应多原子离子干扰的消除试验,建立稻田土壤中Cr、Ni、As、Cd、Pb、Hg的微波消解-电感耦合等离子体质谱(ICP-MS)测定方法。方法通过对硝酸、硝酸-氢氟酸、硝酸-氟硼酸3种不同酸体系消解效果的比较,分别采用硝酸-氢氟酸、硝酸-氟硼酸对稻田土壤样品进行消解,利用ICP-MS对样品中的Cr、Ni、As、Cd、Pb、Hg进行测定。以115In、185Re作为内标同位素,采用干扰校正方程和碰撞反应模式消除钨氧化物(WO+)等多原子离子干扰,标准曲线法定量。结果方法检出限为0.000 25 mg/kg~0.004 7 mg/kg,线性相关系数为0.999 8~1.000 0,土壤标准物质的测定结果均在标准值范围内,相对标准偏差为1.7%~6.1%。结论该方法操作简单,准确可靠,可满足稻田土壤样品中Cr、Ni、As、Cd、Pb、Hg的测定。
OBJECTIVE To establish a microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) system for the determination of Cr, Ni, As, Cd, Pb and Hg in paddy soils by screening different acid systems in microwave digestion and eliminating the interference of polyatomic ions. test methods. Methods By comparing nitric acid, nitric acid-hydrofluoric acid and nitric acid-fluoroboric acid, the digestion effects of three different acid systems were compared. The soil samples were digested with nitric acid-hydrofluoric acid and nitric acid-fluoroboric acid, respectively. In the Cr, Ni, As, Cd, Pb, Hg determination. Using 115In and 185Re as internal standard isotopes, the interference correction equation and collision reaction mode were used to eliminate the interference of polyatomic ions such as tungsten oxide (WO +) and the like, and the standard curve method was used for quantification. Results The detection limits of this method ranged from 0.000 25 mg / kg to 0.004 7 mg / kg, with a linear correlation coefficient of 0.999 8-1.000 0. The results of soil standard materials were all within the standard values with relative standard deviations of 1.7% -6.1% . Conclusion The method is simple, accurate and reliable and can meet the determination of Cr, Ni, As, Cd, Pb and Hg in paddy soil samples.