The Tapioca sample was dissolved with a mixed solution of HNO3 - H2O2(3 +3) by using microwave digestion, and the content of Pb, Cu, Cd, As, Hg in the sample solution was determined by ICP - MS. The becoming isotopes were selected, and the polyatomic ions to cause interference such as Cu, As were eliminated by CCT. The liner calibration curves regression coefficients were 0.999 7 - 0.999 9. Detection limit( 3s) of the method were 0.084, 0.20, 0.024, 0.21,0.32 ng /mL for Pb, Cu, Cd, As, Hg repectively. The relative standard deviations were 1.93% -9. 31% (re =6). The recoveries were 82. 2% - 102% (n = 2).The proposed method was used in determination of Pb, Cu, Cd, As, Hg in 3 national standard samples ( CRM Rice GBW10010, CRM Com GBW10012, CRM Wheat GBW10011). The determination results were in conformity with standard values.%用硝酸-过氧化氢溶液(3+3)作为消解剂,微波消解法处理木薯淀粉等样品,采用电感耦合等离子体质谱法,选择适合的同位素元素,运用碰撞池技术(CCT)降低元素Cu、As的多原子离子干扰,测定样品溶液中Pb、Cu、Cd、As、Hg等元素的含量,各元素线性相关系数为0.9997 ～0.9999,元素的检出限(3sd)分别为pb 0.084 ng/mL、Cu0.20 ng/mL、Cd 0.024 ng/mL、As 0.21 ng/mL、Hg 0.32 ng/mL,各元素相对标准偏差为1.93% ～9.31% (n=6),木薯淀粉样品加标回收率为82.2%～102.0%.用本法测定大米(GBW 10010)、玉米(GBW 10012)和小麦(GBW 10011)3个国家标准物质,测定值均在标称值范围内.
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