Collision induced dissociation reactions

Other means of manipulating ions trapped in the FTMS cell include photodissociation (70-74), surface induced dissociation (75) and electron impact excitation ("EIEIO")(76) reactions. These processes can also be used to obtain structural information, such as isomeric differentiation. In some cases, the information obtained from these processes gives insight into structure beyond that obtained from collision induced dissociation reactions (74). These and other processes can be used in conjunction with FTMS to study gas phase properties of ions, such as gas phase acidities and basicities, electron affinities, bond energies, reactivities, and spectroscopic parameters. Recent reviews (4, 77) have covered many examples of the application of FTMS and ICR, in general, to these types of processes. These processes can also be used to obtain structural information, such as isomeric differentiation. 

TABLE 2 Illustration of the Relationship Between Target Gas Mass and Energy Deposition in Collision-Induced Dissociation Reactions... 

ICR-FTMS experiments have been employed to derive thermodynamic information using several approaches ( ). These include studies of exothermic and endothermic ion-molecule reactions, equilibration studies, competitive collision-induced dissociation reactions, and photodissociation studies. Exothermic reactions involving therma-lyzed (cooled by an inert buffer gas) ions provide brackets on metal-ligand bond enthalpies, as illustrated by Equation 44 which implies that D(Fe-C5H4 ) > 66 kcal/mol. Endothermic reactions can also be studied in the manner described above for ion beam experi-... 

Collision-Induced Dissociation Reactions at Low Kinetic Energies... 

The ARL tandem mass spectrometer has also been used to study collision-induced dissociation reactions using isotopically labeled NO. Surprisingly, these experiments show that the and products from the dissociation of NO are actually derived from both the impacting ion and the neutral target by the reactions... 

The results given j in Table j II show that in perfluorlnated propylene, fragment CF and CF Ions undergo exothermic F transfer reactions with the parent molecule. The only other reactions observed In C Fg as well as In 2-C,Fg (5) are endothermic collision-Induced dissociation reactions. 

K has been identified as CFl200I-I from its chemistry the reaction mechanism is insertion [115], Collision-induced dissociation (in a SIFT apparatus, a triple-quadnipole apparatus, a guided-ion beam apparatus, an ICR or a beam-gas collision apparatus) may be used to detemiine ligand-bond energies, isomeric fomis of ions and gas-phase acidities. 

Collision-induced dissociation mass spectrum of tire proton-bound dimer of isopropanol [(CH2)2CHOH]2H. The mJz 121 ions were first isolated in the trap, followed by resonant excitation of their trajectories to produce CID. Fragment ions include water loss mJz 103), loss of isopropanol mJz 61) and loss of 42 anui mJz 79). (b) Ion-molecule reactions in an ion trap. In this example the mJz 103 ion was first isolated and then resonantly excited in the trap. Endothennic reaction with water inside the trap produces the proton-bound cluster at mJz 121, while CID produces the fragment with mJz 61. 

As with the quadmpole ion trap, ions with a particular m/z ratio can be selected and stored in tlie FT-ICR cell by the resonant ejection of all other ions. Once isolated, the ions can be stored for variable periods of time (even hours) and allowed to react with neutral reagents that are introduced into the trapping cell. In this maimer, the products of bi-molecular reactions can be monitored and, if done as a fiinction of trapping time, it is possible to derive rate constants for the reactions [47]. Collision-induced dissociation can also be perfomied in the FT-ICR cell by tlie isolation and subsequent excitation of the cyclotron frequency of the ions. The extra translational kinetic energy of the ion packet results in energetic collisions between the ions and background... 

Armentrout PB (2003) Threshold Collision-Induced Dissociations for the Determination of Accurate Gas-Phase Binding Energies and Reaction Barriers. 225 227-256 Astruc D, Blais J-C, Cloutet E, Djakovitch L, Rigaut S, Ruiz J, Sartor V, Valerio C (2000) The First Organometallic Dendrimers Design and Redox Functions. 210 229-259 Aug6 J, see Lubineau A (1999) 206 1-39... 

Fragmentation occurs because the repeller voltage increases the kinetic energy of the ions, not only making collision-induced dissociation (CID) more likely but also allowing endothermic ion-molecule and solvent-switching reactions to occur. 

Surface methyls have also been synthesized by the collision-induced dissociation of methane physisorbed on Ni(lll) surfaces.[7, 8] This approach avoids the effects of coadsorbates other than hydrogen, and a number of aspects of Ae reaction and decomposition of CH3 and CH fragments on Ni(lll) have been determined.[9] However, the method is relatively complex and best suited for study of low coverages. 

Collision-induced Dissociation/Translationally-driven Reactions 215... 

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... 

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