Rapid Solution-Phase Hydrogen/Deuterium Exchange for Metabolite Compound Identification.

Area of Science:

• Analytical Chemistry
• Biochemistry
• Physical Chemistry

Background:

• Distinguishing small-molecule metabolites is crucial for biological and chemical research.
• Current methods for metabolite identification can be challenging, especially for complex mixtures.
• Hydrogen/deuterium exchange (HDX) coupled with mass spectrometry (MS) offers a potential avenue for structural elucidation.

Purpose of the Study:

• To demonstrate the utility of rapid, solution-phase HDX coupled with MS for distinguishing small-molecule metabolites.
• To develop a method for quantifying deuterium incorporation efficiencies for different hydrogen types.
• To assess the accuracy of HDX-derived parameters in predicting deuterium incorporation and metabolite identification.

Main Methods:

• Utilizing capillary vibrating sharp-edge spray ionization (cVSSI) for rapid, solution-phase HDX in micrometer-sized droplets.
• Analyzing unique isotopic patterns generated by varying deuterium incorporation efficiencies in MS spectra.
• Employing linear regression to compute exchange parameters representing hydrogen type contributions.

Main Results:

• Different compounds exhibited unique deuterium incorporation efficiencies, leading to distinct isotopic patterns in MS.
• Computed exchange parameters accurately retrodicted the amount of deuterium incorporated, with a ~2.2-fold improvement over equal hydrogen treatment.
• Hypothetical isotopic distributions generated using these parameters agreed well (±16% RMSD) with experimental measurements.

Conclusions:

• Rapid HDX-MS, utilizing cVSSI, is a viable method for distinguishing small-molecule metabolites.
• The developed exchange parameters enhance the accuracy of deuterium incorporation prediction.
• This approach shows significant potential for identifying challenging metabolite species in complex biological samples.