Two is better than one: Deuterium in analytical mass spectrometry

This review explores the diverse applications of deuterium in medicinal chemistry, particularly as an analytical tool in mass spectrometry. Deuterium applications extend beyond its traditional use as an analytical reference material to being integrated into drug structures and tagging reagents for quantitative proteomics. Hydrogen-deuterium exchange (HDX) of labile protons is applied for structural analysis and monitoring protein folding, interactions, and denaturation processes, whereas the metal-catalyzed HDX in C–H bonds provides site-specific deuterium labeling. Deuterated analytical reference materials and labeling reagents are used in the investigation of metabolic pathways, offering valuable insights into drug transformations. Deuterium has evolved into a powerful tool for mass spectrometry-based structural and quantitative analyses, however, challenges such as isotopic effects, chromatographic elution profile differences, and proton mixing in MS analysis still exist, necessitating ongoing technological advancements. [Display omitted] •Deuterium-labeled compounds are synthesized from scratch or obtained through HDX.•Labile proton exchange provides insightful structural information in proteomics.•Deuterated drugs are being approved due to enhanced stability and therapeutic efficacy.•HDX effects are studied by high resolution mass spectrometry.•Deuterium labeled compounds are routinely used in quantitative and qualitative omics.