<p>Alkanesulfonates are widely used as anionic surfactants in detergents, requiring accurate quantitative methods for quality control. This study aimed to develop a deuterated internal standard for sodium alkanesulfonates via hydrogen/deuterium (H/D) exchange using a transition metal catalyst. Generally, sulfonate groups are known to strongly adsorb onto metal surfaces and deactivate catalysts due to their catalyst-poisoning effect. However, we found that alkanesulfonates can be deuterated with a ruthenium on carbon (Ru/C) catalyst in D₂O under a hydrogen atmosphere. The D contents increased with alkyl chain length, ranging from 20 to 86%. Sodium dodecanesulfonate, which showed the highest D content, was selected as the internal standard. A model detergent sample was prepared to evaluate quantification performance. Quantitative analysis was conducted using liquid chromatography–time-of-flight mass spectrometry (LC-TOFMS) with electrospray ionization (ESI) and field desorption (FD)-TOFMS. ESI provided high sensitivity for trace analysis, while FD offered faster measurements for concentrated samples. Spike-and-recovery experiments across a concentration range (0.50–200 ppm) demonstrated that using an internal standard improved measurement accuracy. This approach offers a practical solution for quantifying sulfonate-based surfactants in complex detergent matrices.</p> Graphical abstract