Analytical characteristics, tandem

Analytical characteristics, tandem mass spectrometry, 127-29 Analytical method, volatile aldehydes, 61-77 Apple essence... 

Principles and Characteristics Analytical multistage mass spectrometry (MSn) relies on the ability to activate and dissociate ions generated in the ion source in order to identify or obtain structural information about an unknown compound and to analyse mixtures by exploiting two or more mass-separating steps. A basic instrument for the currently most used form, tandem mass spectrometry (MS/MS), consists of a combination of two mass analysers with a reaction region between them. While a variety of instrument set-ups can be used in MS/MS, there is a single basic concept involved the measurement of the m/z of ions before and after a reaction in the mass spectrometer the reaction involves a change in mass and can be represented as ... 

The analytical performance of four modes of LC-MS, multiple MS (MS"), and tandem MS operation (APCI and ESI with positive and negative ionizations) has been compared for two mass spectrometers, a triple-quadrupole and an ion-trap instrument.With 15 flavonoids as test compounds, the use of APCI in the negative-ion mode gave the best response, with the signal intensities and the mass-spectral characteristics not differing significantly between the two instruments. Under optimum conditions, full-scan limits of detection of... 

Broyles DL, Nielsen RG, Bussett EM, Lu WD, Mizrahi lA, Nunnelly PA, et al. Analytical and clinical performance characteristics of Tandem-MP Ostase, a new... 

Quadrupole ion trap mass analyzers merge the trapping characteristics of the ICR with the physical principles of the linear quadrupole mass analyzer. Quadrupole ion traps produce time-dependent spectra with excellent sensitivity and tandem mass spectrometry capabilities, but unlike the ICR they provide these ion trapping characteristics with physically smaller and considerably less expensive instrumentation, giving them a reputation as a powerful and accessible tool for both qualitative and quantitative mass spectrometry [43-47]. The capability of quadrupole ion traps to be configured with either internal and external ionization sources has expanded their utility for modem analytical applications [48—52]. 

The most widely used tandem mass analyzer for bioanalysis is the triple-quadrupole mass spectrometer (TQMS). In the TQMS format, a characteristic fragmentation transition is monitored for an analyte with more than one mass filter in combination, hence the term MS/MS. A diagram of a TQMS is presented in Figure 11.2. A TQMS consists of two mass selecting quadrupoles, Qi and Q3, and flanked by a center quadrupole (Q2) that acts as a collision cell. Since Q2 is operated in the RF-only mode, mass selection is not performed in this region. The Q2 rods are important, however, since they refocus ions... 

Tandem mass spectrometry (MS/MS) might be an alternative to high resolution MS under some circumstances (e.g., when detection with very high sensitivity is required in a complex matrix). In MS/MS, an ion characteristic for the analyte molecule is selected (so-called parent ion)... 

Medzihradszky, K. R, Campbell, J. M., Baldwin, M. A., Falick, A. M., Juhasz, R, Vestal, M. L., and Burlingame, A. L., The characteristics of peptide collision-induced dissociation using a high-performance MALDI-TOE/TOF tandem mass spectrometer. Analytical Chemistry, 72, 552-558, 2000. 

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