非破坏性开放式激光剥蚀电感耦合等离子体质谱法原位测定大尺寸陶瓷样品主微量元素组成

In-situ Non-destructive Determination of Major and Trace Elements in Large Size Ceramic Samples by Open Laser Ablation Inductively Coupled Plasma-Mass Spectrometry

激光剥蚀电感耦合等离子体质谱法(LA-ICP-MS)通常采用体积固定的封闭剥蚀池,大尺寸样品要经过切割或破碎,能够放入剥蚀池后才可以再进行LA-ICP-MS分析,因此,这种常规密闭式LA-ICP-MS难以应用于无法破碎的珍稀大尺寸样品分析。为实现大尺寸样品的非破坏性微区原位主微量元素分析,本文基于自行设计的开放式样品采集口,结合气体交换装置,建立了开放式LA-ICP-MS分析方法,以大尺寸陶瓷圆盘样品为例,实现了其未经破碎即可直接在敞开的空气环境中进行微区原位主微量元素含量分析。最佳气流速下的氦气作为屏蔽气,在开放式样品采集口周围形成屏障,将激光剥蚀点与空气隔开,同时激光剥蚀产生的分析物气溶胶被屏蔽气聚拢并携带,在样品采集口负压的作用下进入传输管路,通过气体交换装置,高纯氩气置换掉气溶胶中混入的空气,最后进入等离子体质谱被检测。为验证该方法的准确性,将大尺寸陶瓷样品破碎后对开放式LA-ICP-MS分析点邻近区域进行常规密闭式LA-ICP-MS分析,两种方法所检测的51个元素中大部分元素相对误差小于10%,仅部分元素(如磷铍钪钇镧钐铕镝铪钨等)因含量极低相对误差高于20%,显示开放式LA-ICP-MS法具有较好的分析准确度,适用于对大尺寸样品的非破坏性微区原位主微量元素分析。

BACKGROUND:Usually,laser ablation inductively coupled plasma-mass spectrometry(LA-ICP-MS)analysis is equipped with a closed ablation cell.It cannot be used for non-destructive analysis of the large-size samples which exceeds the size of the cell.OBJECTIVES:To realize directly in situ non-destructive analysis of major and trace elements in the large-size samples.METHODS:Based on the self-designed open sample collection port,combined with the gas exchange device,an open LA-ICP-MS analysis method was established.Taking the large-size ceramic disc sample as an example,samples can be directly determined for major and trace elements in an air environment without being broken.RESULTS:Analyte aerosols produced by laser ablation were collected and sucked by open sample collector.The air in the aerosols was replaced via transfer tube by high purity argon in a gas exchange device,the analyte aerosols were then transferred into ICP-MS for detection.After non-destructive analyses by this method,large-size ceramic samples were broken and analyzed by traditional LA-ICP-MS.Relative deviations of most of 51 elements detected by the two methods were less than 10%.Only part of elements(such as P,Be,Sc,Y,La,Sm,Eu,Dy,Hf,W,etc.)had relative deviations higher than 20%,because of the extremely low contents.CONCLUSIONS:The open LA-ICP-MS method is suitable for in situ non-destructive determination of major and trace elements in the large-size samples.