Analytical Determination of Deuterium Atomic Fraction in Hydrogen Isotopes via Quadrupole Mass Spectrometry: Real-Time Monitoring in Liquid-Phase Catalytic Exchange

Accurate quantification of deuterium (D) atomic fractions is fundamental to a wide range of scientific and technological applications involving hydrogen isotopes. This study introduces a novel analytical method for accurately estimating deuterium (D) atomic fractions using quadrupole mass spectrometry (QMS). The method is specifically optimized for low D concentrations and effectively overcomes isobaric ion interference, which often limits the accuracy of conventional QMS-based analysis. Validation experiments were conducted based on liquid-phase catalytic exchange (LPCE) processes and density meter (DM) measurements. The developed method achieved an absolute error of 1.85% at a D concentration of 5%, with even lower errors observed at lower concentrations. The proposed approach enables real-time, cost-effective monitoring of D atomic fractions, providing a reliable tool for hydrogen isotope analysis.