Tandem FTICR

Hakansson, K., Emmett, M.R., Hendrickson, C.L. and Marshall, A.G. (2001) High-sensitivity electron capture dissociation tandem FTICR mass spectrometry of microelectrosprayed peptides, Analytical Chemistry 73,... 

HSkansson, K. Emmet, M.R. Hendrickson, C.L. Marshall, A.G. High-Sensitivity Electron Capture Dissociation Tandem FTICR Mass Spectrometry of Microelectrosprayed Peptides. Anal. Chem. 2001, 73, 3605-3610. 

Different mass analysers can be combined with the electrospray ionization source to effect analysis. These include magnetic sector analysers, quadrupole filter (Q), quadrupole ion trap (QIT), time of flight (TOF), and more recently the Fourrier transform ion cyclotron resonance (FTICR) mass analysers. Tandem mass spectrometry can also be effected by combining one or more mass analysers in tandem, as in a triple quadrupole or a QTOF. The first analyzer is usually used as a mass filter to select parent ions that can be fragmented and analyzed by subsequent analysers. 

The development of mass spectrometric techniques, such as fast atom bombardment mass spectrometry (FAB-MS), ° ° Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), ° and tandem mass spectrometry (MS"), ° allowed enantiodiscrimination of chiral ion-dipole complexes the gas phase. These techniques and others will be illustrated in detail in the next Section 3. 

Electrospray ion source electrospray ioniz., Coulomb repulsion M"+ atmospheric pressure ToF-MS, FTICR-MS tandem MS biomolecules... 

The most common types of MS/MS instruments available to researchers in food chemistry include triple quadrupole mass spectrometers and ion traps. Less common but commercially produced tandem mass spectrometers include magnetic sector instruments, Fourier transform ion cyclotron resonance (FTICR) mass spectrometers, and quadrupole time-of-flight (QTOF) hybrid instruments (Table A.3A.1). Beginning in 2001, TOF-TOF tandem mass spectrometers became available from instrument manufacturers. These instruments have the potential to deliver high-resolution tandem mass spectra with high speed and should be compatible with the chip-based chromatography systems now under development. 

Tandem Mass Spectrometer An instrument capable of performing multiple mass (mjz) analyses. There are two major categories (1) tandem-in-space instruments (triple quadmpole and Q-TOF), (2) tandem-in-time instruments (QIT and FTICR). 

Winger, B. E., and Kemp, C. A. J. (2001). Characterization of pharmaceutical compounds and related substances by using HPLC FTICR-MS and tandem mass spectrometry. Am. Pharrn. Rev. 4 55-56, 58, 60, 62-63. 

Recent innovations in mass spectrometry have provided incorporation of two, three, and four analyzers into commercially available tandem instruments. In addition, different mass analyzers may be combined to form a hybrid mass spectrometer such as the quadrupole-TOF (Q-TOF). Various types of tandem mass spectrometers include the quadruopole-TOF, time-of-flight-time-of-hight (TOF-TOF), triple-quadrupole, and Orbitrap-FTICR configurations. 

Besides this spatial separation method using successive analysers, tandem mass spectrometry can also be achieved through time separation with a few analysers such as ion traps, orbitrap and FTICR, programmed so that the different steps are successively carried out in the same instrument. This method was described in the case of the ion traps and FTMS in Chapter 2. The maximum practical number of steps for these instruments is seven to eight. In these instruments the proportion of ions transmitted is high, but at each step the mass of the fragments becomes lower and lower. 

Trapping-type instrument capable of tandem-in-time experiments and can be configured to analyze fragments generated externally (e.g., QqFTICR or LIT-FTICR). 

Because of these powerful qualitative capabilities, FTICR mass spectrometry is especially useful for characterization of DCLs. Because the composition of the DCL cannot be statically defined, except when in equilibrium with the receptor, it is essential to be able to identify the components at this stage. Using FTICR MS, identification can be done by a combination of exact mass determination and tandem-in-time mass spectrometry to yield par-ent/daughter ion structural information. Although FTICR is an expensive option for combinatorial library characterization, it can provide the most direct information for ligand identification in libraries. 

Commercial LITs were introduced in 2002 as either a stand-alone mass spectrometer (LTQ) [318] or as part of a triple quadrupole (Q-Trap) [319] or in 2005 as part of hybrid tandem mass spectrometers (LTQ-Orbitrap and LTQ-FTICR) [88,90], Application of LTQ-FTICR for metabolism studies has been reviewed by Shipkova et al. [90], In comparison to other mass analyzer types, FTICR-based mass spectrometers are not very popular for metabolite identification studies due to availability of less expensive and more user-friendly LTQ-Orbitrap and Q-TOF-based systems. Another limitation associated with the FTICR-based hybrid mass spectrometers is the TOF effect, which results in efficient trapping of only the high-mass ions [90],... 

In 1994, Oppenheimer and coworkers73 reported a study of the gas-phase generation of arabinosyl oxocarbenium ions via use of tandem positive-ion liquid secondary ion mass spectrometry (LSIMS) (Scheme 37). Plots of log ([oxocarbenium ion]/([M+] +[oxocarbenium ion])) versus rate constants for solvolysis of the same series afford a p of -6.7. While the basis for this difference in p is not clear, it is reasonable to propose that the reaction in the gas phase is similar in nature to the solution reaction. With ion trap or FTICR instrumentation, studies such as these might be extended to following the fate of the oxocarbenium ion as it reacted with nucleophiles introduced into the mass spectrometer. 

Figure 9.2 The basic components of a mass spectrometer. All mass spectrometers consist of an ion source linked to a mass analyser then to a detector. The important ion sources and mass analysers for biological mass spectrometry are listed. There are many other potential ion sources and mass analysers used generally in mass spectrometry, but only the indicated are of use in the analysis of biological macromolecules and amphiphilic lipids, and also in proteomics FAB fast atom bombardment MALDI matrix-assisted laser desorption and ionization ESI electrospray ionization ToF time of flight FTICR fourier transform ion cyclotron resonance MS/MS tandem mass spectrometry.

Jebanathirajah JA, Pittman JL, Thomson BA, Budnik BA, Kaur P, Rape M, Kirschner M, Costello CE, O Connor PB. Characterization of a new qOq-FTICR mass spectrometer for post-translational modification analysis and top-down tandem mass spectrometry of whole proteins. J Am Soc Mass Spectrom 2005 16 1985-1999. 

A variety of mass analyzers have been used in MSI experiments such as TOP, quadrupole ion trap (QIT), linear ion trap (LIT), QqQ, Fourier transform ion cyclotron resonance (FTICR), and Orbitrap. Also, various tandem configurations of these mass analyzers such as QqTOF, QqLIT, and TOF/TOF have been used. Due to the many possible interferenees from endogenous compounds or from the matrix, the use of tandem mass speetrometry (MS/MS or MS") or the ability to perform high-resolution and aeeurate mass measurements for the analysis of drugs by MALDI is essential. An overview of some of the established instrumentation and their respeetive eapabilities is presented below. 

Tandem Mass Spectrometry on FTICR Mass Spectrometers... 

---