Simple and cost-effective methods for precise analysis of trace element abundances in geological materials with ICP-MS  

作　　者：Shuo Chen Xiaohong Wang Yaoling Niu Pu Sun Meng Duan Yuanyuan Xiao Pengyuan Guo Hongmei Gong Guodong Wang Qiqi Xue 

机构地区：[1]Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China [2]Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266061,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]Department of Earth Sciences,Durham University,Durham DH1 3LE,UK [5]School of Earth Science and Mineral Resources,China University of Geosciences,Beijing 100083,China

出　　处：《Science Bulletin》2017年第4期277-289,共13页科学通报（英文版）

基　　金：supported by National Natural Science Foundation of China(41130314 and 41630968);Chinese Academy of Sciences Innovation Grant(Y42217101L);Qingdao National Laboratory for Marine Science and Technology(2015ASKJ03);Marine Geological Process and Environment(U1606401)

摘　　要：Inductively coupled plasma mass spectrometry （ICP-MS） is the most commonly used technique to deter- mine the abundances of trace elements in a wide range of geological materials. However, incomplete sample digestion, isobaric interferences and instrumental drift remain obvious problems that must be overcome in order to obtain precise and accurate results, For this reason, we have done many experi- ments and developed a set of simple, cost-effective and practical methods widely applicable for precise and rapid determination of trace element abundances in geological materials using ICP-MS. Commonly used high-pressure digestion technique is indeed effective in decomposing refractory phases, but this inevitably produces fluoride complexes that create new problems. We demonstrate that the fluoride complexes formed during high-pressure digestion can be readily re-dissolved using high-pressure vessel at 190 ℃ for only 2 h for 50 mg sample. In the case of isobaric interferences, although oxide （e.g., MO^＋/M^＋） and hydroxide （e.g., MO^＋/M^＋） productivity is variable between runs, the （MO^＋/M^＋）/（CeO^＋/Ce^＋） and （MOH^＋/M^＋）/（CeO^＋/Ce^＋） ratios remain constant, making isobaric interference correction for all other elements of interest straightforward, for which we provide an easy-to-use off-line procedure. We also show that mass-time-intensity drift curve is smooth as recognized previously, for which the correction can be readily done by analyzing a quality-control （QC） solution and using off-line Excel VBA procedure without internal standards. With these methods, we can produce data in reasonable agreement with rec- ommended values of international rock reference standards with a relative error of 〈8% and precision generally better than 5%. Importantly, compared to the widely used analytical practice, we can effectively save 〉60% of time （e.g., 〈24 h vs. 〉60 h）.Inductively coupled plasma mass spectrometry(ICP-MS) is the most commonly used technique to determine the abundances of trace elements in a wide range of geological materials. However, incomplete sample digestion, isobaric interferences and instrumental drift remain obvious problems that must be overcome in order to obtain precise and accurate results. For this reason, we have done many experiments and developed a set of simple, cost-effective and practical methods widely applicable for precise and rapid determination of trace element abundances in geological materials using ICP-MS. Commonly used high-pressure digestion technique is indeed effective in decomposing refractory phases, but this inevitably produces fluoride complexes that create new problems. We demonstrate that the fluoride complexes formed during high-pressure digestion can be readily re-dissolved using high-pressure vessel at 190 °C for only 2 h for 50 mg sample. In the case of isobaric interferences, although oxide(e.g., MO+/M+) and hydroxide(e.g., MOH+/M+) productivity is variable between runs, the(MO+/M+)/(Ce O+/Ce+)and(MOH+/M+)/(Ce O+/Ce+) ratios remain constant, making isobaric interference correction for all other elements of interest straightforward, for which we provide an easy-to-use off-line procedure. We also show that mass-time-intensity drift curve is smooth as recognized previously, for which the correction can be readily done by analyzing a quality-control(QC) solution and using off-line Excel VBA procedure without internal standards. With these methods, we can produce data in reasonable agreement with recommended values of international rock reference standards with a relative error of <8% and precision generally better than 5%. Importantly, compared to the widely used analytical practice, we can effectively save >60% of time(e.g., <24 h vs. >60 h).

关 键 词：Inductively coupled plasma mass spectrometry High-pressure digestion Oxide and hydroxide interferences Instrumental drift Correction methods Trace elements 

分 类 号：P624[天文地球—地质矿产勘探]