Preparation and Characterization of Synthetic Lepidolite Reference Material for In-situ Lithium Isotope Analysis via LA-MC-ICP-MS

In-situ microanalytical lithium isotope techniques like laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) are powerful geochemical tools that help study crust-mantle material cycling, silicate weathering, and crustal hydrothermal processes.This work enhances lithium isotope measurement methods in lepidolite by developing a matrix-matched reference material.Natural lepidolite powders were first ground into ultra-fine particles using a planetary ball mill and then rapidly sintered at 700C and 50 MPa for 10 minutes using the fast hot pressing (FHP) technology.The synthesized lepidolite (NWU-LPD) has a smooth surface and dense structure suitable for laser ablation analysis.To assess its isotopic homogeneity, 285 spot analyses using LA-MC-ICP-MS yielded consistent values with an average Li value of 8.74 0.46 (2SD).This uniform lithium isotopic composition in NWU-LPD demonstrates its potential as a matrix-matched reference material for in-situ lithium isotope analysis in natural lepidolite.We also optimized laser settings and established a standard LA-MC-ICP-MS protocol using matrix-matched reference materials in lithium isotope analysis.Finally, solutionbased MC-ICP-MS analyses determine a recommended reference Li value of 8.70 0.28 (2SD, n = 5) for NWU-LPD.