Sustained off- resonance irradiation

Gauthier, J.W. Trautman, T.R. Jacobson, D.B. Sustained Off-Resonance Irradiation for Collision-Activated Dissociation Involving FT-ICR-MS. CID Technique That Emulates Infrared Multiphoton Dissociation. Anal. Chim. Acta 1991,246,211-225. 

Hofstadler, S. A., Wahl, J. H., Bakhtiar, R., Anderson, G. A., Bruce, J. E., and Smith, R. D. (1994). Capillary electrophoresis/Eourier-transform ion-cyclotron-resonance mass spectrometry with sustained off-resonance irradiation for the characterization of protein and peptide mixtures. ]. Am. Soc. Mass Spectrom. 5, 894 —899. 

FT-ICR instruments are also capable of performing MS" experiments. The most popular method of ion activation is sustained off-resonance irradiation (SORI), where ions are excited to a larger cyclotron radius using rf energy, undergo collisions with a neutral gas pulsed into the cell and dissociate. Other methods are available, including infrared multiphoton dissociation (IRMPD)65 and electron capture dissociation (ECD)66 which is of particular value in glyco-peptide analysis (Section VIA). 

Gauthier, J.W., Trautman, T.R. and Jacobson, D.B. (1991) Sustained off-resonance irradiation for collision-activated dissociation involving Fourier transform mass spectrometry. Collision-activated dissociation technique that emulates infrared multiphoton dissociation. 

Hettich, R.L. and Stemmier, E.A. (1996) Investigation of oligonucleotide fragmentation with matrix-assisted laser desorption ionization Fourier-transform mass spectrometry and sustained off-resonance irradiation. Rapid Commun. Mass Spectrom., 10 (3), 321-7. 

Other fragmentation techniques have been introduced [108]. Some of these, e.g., sustained off-resonance irradiation (SORl) and infrared multiphoton dissociation (IRMPD), provide similar fragmentation as in CID, i.e., preferential backbone cleavages at the peptide amide bond (b- and y-ions). Others like electron-capture dissociation (ECD) [109-110] induce different fragmentation reactions, i.e., the formation of c- and z -ions due to cleavage of N-C bonds. 

Initial results with the fragmentation of multiple-eharge protein ions in FT-ICR-MS were achieved, either by in-source CID [159], sustained off-resonance irradiation (SORI) [160], or infrared multiphoton dissoeiation (IRMPD) [161], and later on with electron-capture dissociation [109-110]. 

Dissociation by collisions with a neutral target, or sustained off-resonance irradiation collision-induced dissociation (SORI-CID) (Amster, 1996). 

Fig. 3.21. (a) Spectrum of a stored waveform inverse Fourier-transform (SWIFT) isolated ion at nominal mass 453 m/z. This molecule is present in dissolved organic matter at the Experimental Nutrient Removal wetland outflow, (b) Spectrum of this ion and resulting products after fragmentation by sustained off-resonance irradiation collision-induced dissociation. Formulae in parentheses represent compositions of lost fragments. From these fragments, unambiguous determination of the elemental composition of the precursor ion at 453 m/z is possible. 

Pastor, S. J. and Wilkins, C. L., Sustained off-resonance irradiation and collision-induced dissociation for structural analysis of polymers by MALDI-FTMS, Int J. Mass Spectrom. Ion Processes, 175, 81, 1998. 

Fragmentation of peptide and protein ions in FT-ICR mass spectrometry may be induced by sustained off-resonance irradiation collision-induced dissociation (SORI-CID) [28], infrared multiphoton dissociation (IRMPD) [29,30], blackbody infrared radiative dissociation (BIRD) [31,32], surface-induced dissociation (SID) [33,34], and electron capture dissociation (ECD) [35,36]. These techniques are true MS/MS techniques in which the precursor ion is isolated prior to fragmentation. Additional techniques in which ions are not isolated but fragmented before they... 

Sustained Off-Resonance Irradiation CottisioN-iNDUCED Dissociation (SORI-CID)... 

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