Identification of the aromatic tertiary N-oxide functionality in protonated analytes via ion/molecule reactions in mass spectrometers.
A mass spectrometric method is presented for the rapid identification of compounds that contain the aromatic N-oxide functional group. This method utilizes a gas-phase ion/molecule reaction with 2-methoxypropene that yields a stable adduct for protonated aromatic tertiary N-oxides (and with one protonated nitrone) in different mass spectrometers. A variety of protonated analytes with O- or N-containing functional groups were examined to probe the selectivity of the reaction. Besides protonated aromatic tertiary N-oxides and one nitrone, only three protonated amines were found to form a stable adduct but very slowly. All the other protonated analytes, including aliphatic tertiary N-oxides, primary N-oxides, and secondary N-oxides, are unreactive toward or react predominantly by proton transfer with 2-methoxypropene.
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
Penggao
P
Duan
Todd A
TA
Gillespie
Brian E
BE
Winger
Hilkka I
HI
Kenttämaa
D003497:Cyclic N-Oxides / Q000737:chemistry*; D013058:Mass Spectrometry; D015394:Molecular Structure
D003497:Cyclic N-Oxides