S t r u c tural Characterization of Formoses by Chemical Ionization Mass Spectrometry

Abstract

Structural characterization of formoses has been carried out by chemical ionization mass spectrometry (CIMS) which is reputed to be useful for molecular weight determination afid structural characterization of relatively involatile compounds. While no protonated molecule (MH⁺) was found in the CI mass spectra of (1a), (1b)and (1c) with isobutan e as a reagent gas, the ammonia-mediated CI mass spectra showed definitely the formation of the ammonium adduct ion (M. NH⁴⁺) from which reliable information on the molecular weight was obtained. Ammonia-d₃ was found to be effective for the hydrogen-deuterium (H-D)exchange reaction. The shifting technique using this reagent gas confirmed the ion structures and the number of active hydrogens in formoses. Accordingly, CIMS using a series of three reagent gases, isobutane, ammonia and ammonia-d₃, promises to be useful for the structural characterization of unknown formose samples.