Ion molecule reaction H/D exchange as a probe for isomeric fractionation in chromatographically separated natural organic matter

- The first gas-phase hydrogen/deuterium exchange (HDX) results for fully resolved fulvic acid isobars are presented.
- Gas-phase and solutions phase HDX are contrasted, revealing subtle differences but the same overall trends.
- The first direct evidence for isomeric fractionation of fulvic acids through reversed phase chromatography is presented.