Raman-Based Internal Standardization for Quantitative LA-ICP-MS Analysis of Individual Fluid Inclusions

In quartz-hosted synthetic fluid inclusions, <i>A</i>_ν1(BO3)/<i>A</i>_{ν2(H–O–H)} follows a single linear calibration for 10 and 20 wt % NaCl solutions (<i>y</i> = (8.68 ×10^–5)<i>x</i>, <i>R</i>² = 0.9995), enabling direct determination of elemental B concentrations without salinity-specific calibration. Ab initio molecular dynamics Raman simulations support the molecular basis of this metric.

Using Raman-derived B concentrations as the internal standard yields mean signed deviations of −11.9 to 6.4% and mean absolute relative deviations of 1.9–11.9% for Li, Na, Mg, K, Rb, Sr, and Cs, whereas conventional microthermometry-based Na standardization produces systematic positive deviations of 8.5–38.0%. This strategy improves quantification of B-bearing fluid inclusions and establishes a general analytical framework for quantitative multielement analysis of aqueous systems containing Raman-active dissolved species.