电感耦合等离子体质谱法分析高纯金属银中痕量杂质元素

Determination of trace impurity elements in high purity metal silver by inductively coupled plasma mass spectrometry

高纯金属纯度分析时为了克服基体效应的影响,常采用分离基体的方法对其中痕量杂质元素进行分析测定,不仅前处理过程较为复杂,且易造成样品污染。实验以硝酸（1＋1）溶解样品,在利用电感耦合等离子体质谱（ICP-MS）半定量法确定高纯银中杂质种类的基础上,通过选择适当的同位素克服了质谱干扰,采用标准加入法绘制校准曲线,在不分离基体的前提下消除了银基体对痕量杂质元素测定的基体效应影响,最终实现了ICP-MS对高纯金属银中铅、砷、铜、镍、锑、锡、钯、铋8种痕量金属杂质的直接定量测定。同时在采用ICP-MS法对高纯金属银中8种痕量金属杂质元素测定后,可根据国标方法GB/T 21198.5—2007中差减法最终计算得到银的纯度。方法的检出限为0.09～1.1μg/L,将实验方法应用于高纯金属银的实际样品分析,加标回收率为96%～106%,相对标准偏差（RSD,n=6）不大于5.0%。

During the purity analysis of high purity metals,the matrix separation method is usually adopted to eliminate the influence of matrix effect for determination of trace impurity elements.However,the pretreatment process is complex and the sample is easily polluted.After the sample was dissolved with nitric acid（1＋1）,the types of impurities in high purity silver were semi-quantitatively determined by inductively coupled plasma mass spectrometry（ICP-MS）.Then,the mass spectrometry interference was overcome by selecting proper isotopes,and the calibration curves were prepared by standard addition method.Consequently,the influence of matrix effect of silver in determination of trace impurity elements could be eliminated without matrix separation,realizing the direct quantitative determination of eight trace metallic impurities（including lead,arsenic,copper,nickel,antimony,tin,palladium and bismuth）in high purity metal silver by ICP-MS.Moreover,after the determination of eight trace impurity elements in high purity metal silver by ICP-MS,the purity of silver could be calculated by subtraction method according to national standard method GB/T 21198.5-2007.The detection limit of method was 0.09-1.1μg/L.The proposed method was applied to the analysis of high purity metal silver actual samples.The recoveries of standard addition were between 96% and 106%.The relative standard deviations（RSD,n=6）were not more than 5.0%.