Distinguishing between Isobaric Ions Using Microdroplet Hydrogen-Deuterium Exchange Mass Spectrometry

Isobaric ions having the same mass-to-charge ratio cannot be separately identified by mass spectrometry (MS) alone, but this limitation can be overcome by using hydrogen-deuterium exchange (HDX) in microdroplets. Because isobaric ions may contain a varied number of exchangeable sites and different types of functional groups, each one produces a unique MS spectral pattern after droplet spray HDX without the need for MS/MS experiments or introduction of ion mobility measurements. As an example of the power of this approach, isobaric ions in urinary metabolic profiles are identified and used to distinguish between healthy individuals and those having bladder cancer.

Automated summary

Isobaric ions with the same mass-to-charge ratio can be differentiated using hydrogen-deuterium exchange in microdroplets, producing unique MS spectral patterns without the need for MS/MS experiments or ion mobility measurements. This approach has been successfully used to identify isobaric ions in urinary metabolic profiles and distinguish between healthy individuals and those with bladder cancer.