High precision measurement of trace F and Cl in olivine by electron probe microanalysis

Abstract Fluorine (F) and chlorine (Cl) are important volatiles in olivine its high-pressure polymorphs, which would significantly affect phase transition, melting temperature, physical property of the mantle. F Cl concentrations can be detected by electron probe microanalysis (EPMA). However, analytical accuracy precision impeded severe peak overlaps, low intensities traditional crystals, secondary fluorescence effects. In this study, we constructed an optimized method with high to analyze trace olivine. Key parameters beam conditions, effects were discussed. Variations levels analyzed elements fall within ± 10%. The detection limits (3σ) for lowered 30 ppm 5 ppm, respectively. This provide precise analysis natural samples help significant information on formation process.