普通模式ICP-MS与碰撞反应接口模式ICP-MS法测定扇贝和茶叶标准物质中砷的比较

Comparison of the Determination of As in Standard Materials of Scallop and Tea by Normal Mode and CRI Mode ICP-MS

建立了ICP-MS测定扇贝和茶叶标准物质中砷含量的分析方法.采用微波消解法消解样品后分别用普通模式和碰撞反应接口（CRI）模式对其进行了ICP-MS分析,在线^72Ge内标溶液校正仪器的信号漂移.通过比较两种模式对元素砷的测定差异发现：CRI模式下测得的结果更加准确,检测限更低;两种模式下的仪器检测限分别为40.1 ng/L和1.6 ng/L,相对标准偏差在1.1%-5.8%之间.另外,通过测定不同浓度的NaCl基体溶液中的砷的信号,讨论了CRI技术对^40Ar^35Cl^＋造成的干扰的消除情况,证明了CRI技术能有效消除基体中产生的^40Ar^35Cl^＋对样品中^75As^＋测定的干扰,适用于复杂基体样品中砷的测定.

A method was developed for the determination of As in standard materials of Scallop and tea by ICPMS. After the microwave digestion, the samples were directly determined by ICP MS with normal mode and collision reaction interface（CRI） mode, ^72 Ge was used as on-line internal standard to correct the matrix interference and the instrument＇s drift. The difference between the two analysis mode was compared, the accuracy and the detection limit of CRI mode were more superior than that of normal mode. The detection limits of the normal mode and CRI mode were 40.1 ng/L and 1.6 ng/L, respectively, the RSDs were between 1. 1% and 5.8%. In addition, signals of As in different concentration solution of NaCl were determined to discuss the effect of the removal of ^40Ar^35Cl^＋ by CRI mode, the experimental results showed that CRI technique is fit for the analysis of As in complex matric samples for its good behavior in elimination of the interference caused by ^40Ar^35Cl^＋.