低温剥蚀LA-ICP-MS准确测定硫化物矿物多元素分析研究  

Multi-element Accurate Analysis of Sulfide Minerals by Low-temperature Ablation LA-ICP-MS

作　　者：李会来 李凡 张鼎文 郭伟 靳兰兰 胡圣虹 LI Huilai;LI Fan;ZHANG Dingwen;GUO Wei;JIN Lanlan;HU Shenghong(State Key Laboratory of Biogeology and Environmental Geology,College of Earth Sciences,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)生物地质与环境地质国家重点实验室,中国地质大学(武汉)地球科学学院,湖北武汉430074

出　　处：《岩矿测试》2023年第5期970-982,共13页Rock and Mineral Analysis

基　　金：国家重点研发计划项目(2021YFC2903000)课题“战略性矿产微区原位分析技术及应用”。

摘　　要：硫化物矿物中元素含量及其分布可示踪硫化物成矿过程、辨别金属来源和沉积过程的物理化学条件,在地质学、矿床学等领域具有重要的应用价值。激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)已成功应用于硫化物矿物元素微区分析研究,但激光与物质作用产生的热效应严重制约分析结果的可靠性。本文建立了一种高精密度、高准确度的低温剥蚀LA-ICP-MS测定硫化物矿物多元素方法。采用自行研制的Peltier低温剥蚀池可有效抑制硫化物矿物LA-ICP-MS分析中的热效应,提高分析结果的精密度和准确度。扫描电子显微镜(SEM)表明:在低温(-30℃)条件下可在一定程度地抑制激光剥蚀引起的热效应,减少样品熔化和气溶胶气相再沉积;而通过气溶胶颗粒分析发现低温剥蚀可以减小样品气溶胶颗粒的平均尺寸,得到的颗粒粒径分布范围也较小。不同元素信号强度的精密度(RSD)从常温下的20.1%~34.4%改善到11.5%~15.8%,元素的检出限为0.054~0.077μg/g。将该低温LA-ICP-MS系统应用于实验室内部标样黄铜矿Ccp-1分析,测定值与参考值之间的标准偏差在7%以内。BACKGROUND:Micro-geochemical information of sulfide minerals plays a crucial role in the field of geochemistry,allowing discovery of the formation mechanism and evolution process of sulfide minerals by analyzing their element composition characteristics.LA-ICP-MS is currently the most popular microanalysis technology used for sulfide analysis,having yielded successful results.Due to their unique physical and chemical properties,sulfide mineral samples show different laser ablation behavior to conventional geological samples.The most intuitive phenomenon is the melting of ablation carters caused by laser thermal effect and the deposition of a large number of material particles around the ablation carters,which is the main factor limiting the precision and accuracy of sulfide sample analysis.Walting et al[13]found that direct quantitation of multi-elements in sulfide minerals by infrared laser(1064-nm Nd:YAG laser)was impossible,which was because the strong thermal effect generated by the infrared laser will lead to severe large particle aerosol redeposition.It is reported that ablation systems with shorter wavelengths,such as ultraviolet lasers,including the 266 and 213nm laser,can be used to obtain acceptable analytical accuracy by reducing the thermal effect and aerosol particle size,but a poor precision was still observed[16-17].Guillong et al[19]conducted a comparative study of 266,213 and 193nm lasers and found that there were finer particle sizes of the aerosols and the weaker thermal effect when using 193nm laser ablation,and the RSDs of all elements less than 20%were obtained.In other words,collisions between photons and matter intensify in deep ultraviolet laser ablation systems(193nm)with shorter wavelength[20-21]and can help reduce the melt zone and aerosol particle size.However,there is still a slight thermal effect during 193nm UV laser ablation.Fernández et al[22]found that there is still a melting layer during 193nm laser ablation,and it leads to the formation of large particle aerosols.Different m

关 键 词：低温剥蚀池 硫化物矿物 激光剥蚀行为 热效应 LA-ICP-MS 

分 类 号：O657.63[理学—分析化学] P578.2[理学—化学]