Validation of Trace Element Analysis of Geological Materials by Single-Pulse Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS)

Abstract

Laser ablation–inductively coupled plasma – mass spectrometry (LA–ICP–MS) is a powerful tool for determining the elemental and isotopic compositions of various samples. The disadvantage of LA–ICP–MS is that it consumes more sample material than other types of in situ analytical methods. To extend the application of this method to trace element analysis, we conducted single-pulse LA–ICP–MS analysis of the Reference Materials of the National Institute of Standards and Technology (SRM 610, 612, and 614) and the United States Geological Survey (BCR-2G, BHVO-2G, and BIR-1G). The accuracy of the determined concentrations and the precision of the single-pulse LA–ICP–MS analysis were verified by comparison with recommended concentrations for these standards and those obtained by conventional analysis with the same system. Time-resolved profiles of the analyzed elements in the glass samples show that the background-corrected intensity reaches a peak immediately after the start of the laser pulse and then gradually decreases. During each analysis, the isotope ratios are stable until the background-corrected intensity of the elements reaches 5% of the peak values. The relative standard deviation of the single-pulse LA–ICP–MS analyses is significantly higher than for conventional LA–ICP–MS analysis. However, most of the determined concentrations obtained from the reference materials except for NIST SRM614, NIST SRM612, BCR-2G, and BHVO-2G mostly agreed with the recommended values within 20%. In addition, the geochemical features of basaltic reference glasses were accurately reproduced by the single-pulse LA–ICP–MS analyses. In conclusion, the single-pulse LA–ICP–MS method provides usable results for the determination of multiple trace elements in geological materials.

Keywords:

• Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS)
• single-pulse laser sampling
• geological materials
• trace element analysis

Acknowledgements

We would like to thank Noriko Hasebe and Keisuke Fukushi for their help in maintaining the laboratory environment. Comments from two anonymous reviewers and the editor greatly improved the revised manuscript.

Additional information

Funding

This work was partially supported by the Kanazawa University (grant number SAKIGAKE 2020) and the Ministry of Education Culture, Sports, Science, and Technology of Japan (Grants-in-Aid numbers 18H01303 (KO), 19H01990 (TM), and 19KK0092 (TM)).