电感耦合等离子体质谱法测定土壤中重金属有效态浓度

ICP/MS for determination of bio-available heavy metals in soil samples

采用电感耦合等离子体质谱(ICP/MS)法,结合内标技术,高效、快速地测定了土壤中Cu、Zn、Pb、Cd、Ni、Cr、Hg、As和Se9种元素的有效态浓度。Cu、Zn、Pb、Cd、Ni、Cr、Hg的有效态采用0.1mol/LNaNO3浸提,所得浸提液上机前预先稀释10倍;As和Se的有效态采用稀HCl浸提。结果表明,在测定所有空白、标准溶液及样品时均在线加入500μg/L45Sc/72Ge/209Bi内标溶液,有效地克服了基体效应、接口效应和仪器波动所产生的影响;0.15%(质量分数)NaCl-1.0%(体积分数)HCl作为Hg标准溶液固定液,可保证1μg/LHg标准溶液7d有效期;9种元素有效态的仪器检出限均在μg/L级以下,方法检出限<0.030mg/kg,平均加标回收率为81%～121%,相对标准偏差为0.02%～1.21%。

Inductively coupled plasma mass spectrometry （ICP/MS） was applied to measure the bio-available concentrations of 9 heavy metals （Cu, Zn, Pb, Cd, Ni, Cr, Hg, As and Se） in soil samples. After leaching by 0.1 mol/L NaNO3, solid-liquid separation, and the dilution of 10 factor, the internal standard solution of 500μg/L ^45Sc/^72 Sc/^209 Bi was spiked to all liquid samples before the analysis of Cu, Zn, Pb, Cd, Ni, Cr and Hg. The leaching solution for As and Se was diluted HCl. The internal standard technique effectively overcame the difficulties due to physical interferences, interface and fluctuation of the instrument. By optimizing the operating parameters, employing suitable metal isotopes and correction equations, the adverse effect of mass spectrometry interferences was significantly reduced. The 1 μg/L Hg solution prepared in 0. 15% NaCl-1.0% HCl, with a stable period of 7 days, was the best of the three stabilized Hg solutions prepared. The Apparatus detection limits of the 9 metals were 〈1.0 μg/L, the method detection limits were〈0. 030 mg/kg; the recoveries for spiked metals ranged 81%-121% and that the relative standard deviation was 0.02%-1.21%.