Mass spectrometry electron-induced dissociations

The ability of mass spectrometry to induce chemical transformations makes this method a unique technique for obtaining information about the intrinsic properties of isolated ions and molecules, solvates, clusters, non-covalent complexes, etc. Mass spectrometry is a convenient method for measuring basic thermochemical values of neutral molecules, ions, and radicals. Various molecular properties, such as ionization energy, proton affinity, electron affinity, energy of solvation/ desolvation, and bond dissociation energy can be directly measured in the gas phase by mass spectrometric methods (see also Chapter 2.12). 

Figure 16.1. Typical ranges of activation times associated with various activation methods in tandem mass spectrometry. EID, electron-induced dissociation SID, surface-induced dissociation CA, collisional activation (beam), typical conditions used in a beam-type tandem mass spectrometer ICR-SORI, ion cyclotron resonance sustained off-resonance irradiation cw IRMPD, continuous-wave infrared multiphoton dissociation. (Reproduced from Ref. 15 with permission from John Wiley Sons.)...

DGE a AC AMS APCI API AP-MALDI APPI ASAP BIRD c CAD CE CF CF-FAB Cl CID cw CZE Da DAPCI DART DC DE DESI DIOS DTIMS EC ECD El ELDI EM ESI ETD eV f FAB FAIMS FD FI FT FTICR two-dimensional gel electrophoresis atto, 10 18 alternating current accelerator mass spectrometry atmospheric pressure chemical ionization atmospheric pressure ionization atmospheric pressure matrix-assisted laser desorption/ionization atmospheric pressure photoionization atmospheric-pressure solids analysis probe blackbody infrared radiative dissociation centi, 10-2 collision-activated dissociation capillary electrophoresis continuous flow continuous flow fast atom bombardment chemical ionization collision-induced dissociation continuous wave capillary zone electrophoresis dalton desorption atmospheric pressure chemical ionization direct analysis in real time direct current delayed extraction desorption electrospray ionization desorption/ionization on silicon drift tube ion mobility spectrometry electrochromatography electron capture dissociation electron ionization electrospray-assisted laser desorption/ionization electron multiplier electrospray ionization electron transfer dissociation electron volt femto, 1CT15 fast atom bombardment field asymmetric waveform ion mobility spectrometry field desorption field ionization Fourier transform Fourier transform ion cyclotron resonance... 

Mass spectrometry (MS) and tandem mass spectrometry (MS/MS) play an important role in the identification of unknown compounds. Different ionization techniques have been used in studying isothiazole derivatives, such as electronic ionization (El), desorption chemical ionization (DCI), fast atom bombardment (FAB), field desorption (FD), and chemical ionization (Cl). Different MS/MS experiments have been described, such as investigation of metastable and collision-induced dissociations to study isothiazoles gas-phase ion chemistry. In addition, MS and MS/MS have been used to differentiate isothiazole isomers differing in the position of endocyclic groups or exocyclic substituents <1998THS(2)471, 1999THS(3)369, 2000THS(4)405>. 

---