Characterization of ammonium nitrate by electrospray ionization tandem mass spectrometry

Mass spectra of ammonium nitrate were recorded in both positive- and negati ve-ion mode by electrospray ionization mass spectrometry (ESI-MS) and elect rospray ionization tandem mass spectrometry with collision-induced dissocia tion (ESI-MS/MS-CID). Characterization of ammonium nitrate by a series of t ypical cluster ions was further confirmed by using isotopically labeled amm onium nitrate (ammonium-N-15, nitrate-N-15, nitrate-O-18) and deuterated wa ter. It was found that, at heated capillary temperatures in the range 55-15 0 degreesC, in the positive-ion mode, cluster ions of the type [(NH4NO3)nNH (4)](+)(n = 1-3) were dominant in the mass spectrum, which enables the char acterization and identification of the integral ammonium nitrate molecule. Copyright (C) 2001 John Wiley & Sons, Ltd.