电感耦合等离子体质谱法测定硅藻土助滤剂中的重金属元素

建立了硅藻土助滤剂中多个重金属元素的分析方法。以氢氟酸、硝酸和磷酸为混合试剂采用微波消解法对硅藻土助滤剂进行密闭消解，应用电感耦合等离子体质谱(ICP-MS)法对消解液中的Be，Cr，Ni，As，Cd，Sb，Sn，Tl，Hg，Pb等10个元素进行测定。研究了高硅基体存在时所产的质谱干扰，首先通过优化仪器工作参数以及待测元素同位素的选择，最大程度地避免了质谱分析过程中的多种干扰，然后选择动态反应（DRC）技术消除了其它质谱干扰，多元素（Li，Sc，Y，In，Bi）内标溶液的使用消除了基体效应，维持了分析信号的稳定。分析结果显示，10个待测元素的检出限在3.29～15.68 ng·L-1之间，相对标准偏差（RSD）≤4.62%，加标回收率为90.71%～107.22%。方法的灵敏度高，准确度和精密度好，可用于硅藻土助滤剂的质量控制和安全评价。

Determination of Heavy Metal Elements in Diatomite Filter Aid by Inductively Coupled Plasma Mass Spectrometry

This study established a method for determining Be, Cr, Ni, As, Cd, Sb, Sn, Tl, Hg and Pb, total 10 heavy metals in diatomite filter aid. The diatomite filter aid was digested by using the mixture acid of HNO₃+HF+H₃PO₄ in microwave system, 10 heavy metals elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). The interferences of mass spectrometry caused by the high silicon substrate were optimized, first the equipment parameters and isotopes of test metals were selected to eliminate these interferences, the methane was selected as reactant gas, and the mass spectral interferences were eliminated by dynamic reaction cell (DRC). Li, Sc, Y, In and Bi were selected as the internal standard elements to correct the interferences caused by matrix and the drift of sensitivity. The results show that the detection limits for analyte is in the range of 3.29～15.68 ng·L-1, relative standard deviations (RSD) is less than 4.62%, and the recovery is in the range of 90.71%～107.22%. The current method has some advantages such as, high sensitivity, accurate, and precision, which can be used in diatomite filter aid quality control and safety estimations.