动态反应池-电感耦合等离子体质谱法同时测定地质样品中的金和银

Determination of Au and Ag in geological samples by dynamic reaction cell-inductively coupled plasma mass spectrometry

采用电感耦合等离子体质谱法(ICP-MS)测定地质样品中的痕量Au和Ag时会受到Zr,Nb,Ta,Hf元素的氧化物和氢氧化物的干扰,本研究利用碰撞反应池(DRC)技术,采用O_2作为反应气,将干扰物氧化成多氧化物和/或多氧氢化物以消除干扰,同时通入CH_4修饰Ar等离子体,提高Au和Ag的灵敏度,建立了ICP-MS同时测定地质样品中Au和Ag的方法。在反应气O_2流速为2.2 mL/min时,Ag在m/z 109处的干扰可以降低250多倍,Au在m/z 197处的干扰可以降低500多倍。修饰气CH_4流速为3 mL/min时,Au和Ag的灵敏度分别可以提高3倍和1.5倍。在优化的条件下,Au和Ag的定量限分别为0.01 ng/g和0.007 ng/g。该方法采用岩石标准参考物质进行了验证,结果令人满意。

Au and Ag are subjected to significant spectral interferences caused by high concentrations of Zr, Nb, Ta and Hf in inductively coupled mass spectrometry （ICP-MS） analysis for geological plasma at 3 mL/min, and the sensitivities of Au and Ag were increased by a factor of 3 and 1.5. Under the optimized experimental conditions, the limit of quantitation for Au and Ag were 0. 01 and 0. 007 ng/g, respectively. The proposed method was applied to the direct determination of Au and Ag in geological standard reference materials, and the results were found to agree well with the certified values.