Active hydrogen by chemical ionization mass spectrometry

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Organic Chemistry

Background:

• Accurate determination of active hydrogens is crucial for understanding chemical reactivity and biological function.
• Existing methods may have limitations in scope or precision for diverse functional groups.

Purpose of the Study:

• To develop and describe a novel method for quantifying active hydrogens in hydroxyl, carboxyl, sulfhydryl, amino, amido, and sulfonamido groups.
• To apply chemical ionization mass spectrometry (CIMS) with ammonia and trideuterioammonia for this determination.

Main Methods:

• Utilized chemical ionization mass spectrometry (CIMS) with ammonia (NH3) and trideuterioammonia (ND3) as reagent gases.
• The method relies on the exchange of active hydrogen atoms for deuterium during the ionization process.
• Quantification is achieved by comparing the mass-to-charge (m/z) ratios of specific ion adducts ([M + NH4]+ vs. [M--nH + nD + ND4]+ or [M + H]+ vs. [M--nH + nD + D]+).

Main Results:

• Successfully demonstrated the determination of active hydrogens in various functional groups.
• The deuterium exchange method provides a reliable way to identify and quantify the number of active hydrogens.
• The method was applied to several classes of biologically relevant compounds.

Conclusions:

• Chemical ionization mass spectrometry with trideuterioammonia offers a robust approach for active hydrogen determination.
• This method enhances the characterization of molecules with diverse hydrogen-bonding capabilities.
• The technique has broad applicability in the analysis of biologically important compounds.