微波消解-电感耦合等离子体质谱法测定滑石粉中多种痕量金属元素

Determination of multiple trace elements in talcum powder by inductively coupled plasma mass spectrometry after microwave digestion

样品经微波消解后,应用电感耦合等离子体质谱法测定了滑石粉中Pb、Cd、Cr、As、Sb、Cu、Zn、Mn、Ni、Mo、Co、Sr共12种痕量金属元素。考察了微波消解体系、质谱干扰和基体效应等因素对测定的影响。结果表明:在最佳消解程序(在250W消解2min,在0 W停留2min,在450W消解5min,在550W消解5min)下15mL硝酸能够完全消解0.5g滑石粉样品,质谱干扰可以通过选择同位素以及校正方程消除,基体效应的影响可以在线加入合适的内标元素克服。将方法应用于实际样品分析,待测元素的加标回收率在95%～109%之间,相对标准偏差(RSD,n=8)在2.1%～12.0%范围,测定结果与石墨炉原子吸收光谱法(GF-AAS)、电感耦合等离子体原子发射光谱法(ICP-AES)和氢化物-原子荧光光谱法(HG-AFS)基本吻合。

After microwave digestion,the content of 12 trace metal elements in talcum powder was determined by inductively coupled plasma mass spectrometry,including Pb,Cd,Cr,As,Sb,Cu,Zn,Mn,Ni,Mo,Co and Sr.The results showed that 0.5 g of talcum powder sample could be fully digested with 15 mL of nitric acid under optimal digestion procedures（digestion at 250 W for 2 min,keeping at 0 W for 2 min,digestion at 450 W for 5 min and then digestion at 550 W for 5 min）.The mass spectrometric interference could be eliminated by selecting isotopes and using correction equation.The influence of matrix effect could be overcome by on-line adding proper internal standard elements.The proposed method was applied to the analysis of actual samples.The recoveries of testing elements were between 95 % and 109 %.The relative standard deviations（RSD,n=8） were in range of 2.1 %-12.0 %.The determination results were consistent with those obtained by graphite furnace atomic absorption spectrometry（GF-AAS）,inductively coupled plasma atomic emission spectrometry（ICP-AES） and hydride generation atomic fluorescence spectrometry（HG-AFS）.