CID mass spectrometry

Giguere and Mayer [121] reported on the dissociation of gas-phase poly(vinyl acetate) (PVAc), see Figure 21, ionised by Li+ investigated by electrospray-ionisation (ESI) mass and collision induced dissociation (CID) mass spectrometry. 

Scheme 36) . Deuterium labelling of the starting steroid allows one to distinguish the two forms and determine their fragmentation by CID mass spectrometry. The enolate ion [134 — fragments by heterolysis of the ester bond to generate the complex... 

Cobalt(II)-phthalocyamnetetrasulfonate, as oxidation catalyst 1202 Collision-induced dissociation (CID) mass spectrometry 275, 293 Complexes,... 

Later, gaseous 1,3,5-cyclooctatiiene radical cations 12 were also studied by CID mass spectrometry, together with the ions generated from the acyclic isomo", 1,3,5,7-octatetraene... 

From a partial hydrolysate of A21978 C an ether-soluble fraction was isolated, which was methylated with diazomethane. The mass spectrum of this material (prepared from fraction Ci) gave a molecular ion at m/z 386 and ion fragments at m/z 201 and 130, and was identical with the mass spectrum of authentic N-undecanoyltryptophan methyl ester. Studies of the N-acyltryptophan prepared from fractions C, C2 and C3 by El mass spectrometry of the methyl esters and by CID mass spectrometry of the carboxylate ions in the negative mode showed that Cj contained 9-methyldecanoic acid (anteiso-Cn), C2 10-methylundecanoic acid (iso-Ci2) and C3 10-methyldodecanoic acid (anteiso-Ci3) (725). 

S.3.4.2. Collision-induced Dissociation/Translationally-driven Reactions Tandem-mass spectrometry can be used to determine the threshold energy for collision-induced dissociation (CID),... 

In most cases, ion activation in the reaction region or fragmentation zone is applied to increase the internal energy of the ions transmitted from the ion source. The most common means of ion activation in tandem mass spectrometry is collision-induced dissociation. CID uses gas-phase collisions between the ion and neutral target gas (such as helium, nitrogen or argon) to cause internal excitation of the ion and subsequent dissociation... 

Tandem mass spectrometry has become an important tool for determining the sequence of amino acids in protonated peptides98 and the sequence of bases in deprotonated nucleic acids such as DNA.99 Despite the importance and widespread use of CID-MS to sequence peptides and nucleic acids, the mechanistic details of the dissociation processes are poorly understood. A better understanding of the... 

CID collision-induced dissociation ESI electrospray ionization MS mass spectrometry... 

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... 

In principle, it would be possible to perform multistage mass spectrometry like in an ICR analyzer although with no gas CID would of course not be possible, but other dissociation methods could be employed. There might, however, be technical issues. At the time of writing, fragmentation is performed in the linear QIT preceeding the orbitrap in Thermo Fischer Scientific s instrument. Both pulsed and continuous ion sources can be employed. There are several ion sources that can be employed with Thermo Fischer Scientific s orbitrap. 

Fig. 11.16. Representation of three tandem mass spectrometry (MS/MS) scan modes illustrated for a triple quadrupole instrument configuration. The top panel shows the attributes of the popular and prevalent product ion CID experiment. The first mass filter is held at a constant m/z value transmitting only ions of a single mlz value into the collision region. Conversion of a portion of translational energy into internal energy in the collision event results in excitation of the mass-selected ions, followed by unimolecular dissociation. The spectrum of product ions is recorded by scanning the second mass filter (commonly referred to as Q3 ). The center panel illustrates the precursor ion CID experiment. Ions of all mlz values are transmitted sequentially into the collision region as the first analyzer (Ql) is scanned. Only dissociation processes that generate product ions of a specific mlz ratio are transmitted by Q3 to the detector. The lower panel shows the constant neutral loss CID experiment. Both mass analyzers are scanned simultaneously, at the same rate, and at a constant mlz offset. The mlz offset is selected on the basis of known neutral elimination products (e.g., H20, NH3, CH3COOH, etc.) that may be particularly diagnostic of one or more compound classes that may be present in a sample mixture. The utility of the two compound class-specific scans (precursor ion and neutral loss) is illustrated in Fig. 11.17.

The development glycopeptide libraries obtained by the split-mix method is severely hampered by the lack of concurrent development of a general, facile separation and characterization technology. Some headway has been made with chemical coding of the libraries, but very few direct methods of analysis exist. One promising method that could be applied to the direct characterization of both types of libraries is mass spectrometry. More specifically, post-source-decay matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (PSD-MALDI-TOF-MS) and CID-FAB/MS/MS have been used to characterize glycopeptides.53-55... 

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