Quadrupole-time-of-flight mass spectrometer

Figure 3.10 Schematic of a quadrupole-time-of-flight mass spectrometer. From applications literature published by Micromass UK Ltd, Manchester, UK, and reproduced with permission.

The instrumental analysis for the identification of UV filters degradation products formed during the fungal treatment process was performed by means of HPLC coupled to tandem mass spectrometry using a hybrid quadrupole-time-of-flight mass spectrometer (HPLC-QqTOF-MS/MS). Chromatographic separation was achieved on a Hibar Purospher STAR HR R-18 ec. (50 mm x 2.0 mm, 5 pm, from Merck). In the optimized method, the mobile phase consisted of a mixture of HPLC grade water and acetonitrile, both with 0.15% formic acid. The injection volume was set to 10 pL and the mobile phase flow-rate to 0.3 mL/min. 

With the introduction of the quadrupole time-of-flight mass spectrometers (Morris et al., 1996), it became possible to generate isotopically... 

Loboda A.V., Krutchinsky A.N., Bromisrski M., Ens W., and Standing K.G. (2000), A tandem quadrupole/time of flight mass spectrometer with a matrix-assisted laser desorption/ionization source design and performance, Rapid Commun. Mass Spectrom. 14, 1047-1057. 

Figeys, D., Lock, C., Taylor, L., and Aebersold, R. (1998). Microfabricated device coupled with an electrospray ionization quadrupole time-of-flight mass spectrometer protein identifications based on enhanced-resolution mass spectrometry and tandem mass spectrometry data. Rapid Commun. Mass Spectrom. 12, 1435 — 1444. 

J. H. Beattie, L Joncour, K. et al. Increasing throughput and information content for in vitro drug metabolism experiments using ultra-performance liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer. Rapid Commun Mass Spectrom 2005, 19, 843-848. 

Nassar, A. E. (2003). Online hydrogen-deuterium exchange and a tandem-quadrupole time-of-flight mass spectrometer coupled with liquid chromatography for metabolite identification in drug metabolism. J. Chromatogr. Sci. 41 398-404. 

Common tandem-in-space instruments employ a quadrupole as the first mass analyzer, a multipole collision cell (usually hexapole) operated in RF-only mode, and then either a second quadrupole or a TOF tube as the second mass analyzer. These instruments are termed triple or tandem quadrupole and quadrupole-time-of-flight mass spectrometers. 

D. J. Harvey, R. H. Bateman, R. S. Bordoli, and R. Tyldesley, Ionisation and fragmentation of complex glycans with a quadrupole time-of-flight mass spectrometer fitted with a matrix-assisted laser desorption/ionisation ion source, Rapid Commun. Mass Spectrom., 14 (2000) 2135-2142. 

Griffin, T. J. Gygi, S. P. Rist, B. Aebersold, R. 2001. Quantitative pro-teomic analysis using a MALDI quadrupole time-of-flight mass spectrometer. Anal. Chem, 73,978-986. 

Shevchenko A. Chernushevich, I. Ens, W. Standing, K. G. Thomson, B. Wilm, M. Mann, M. 1997. Rapid de novo peptide sequencing by a combination of nanoelectrospray, isotopic labeling and a quadrupole/ time-of-flight mass spectrometer. Rapid Commun. Mass Spectrom., 11, 1015-1024. 

For example, Liu and Hop [19] described the hepatocytic incubation of a drug candidate possessing a methoxy substituent (RCH2OCH3). The resultant observation of a compound isobaric (at low resolution) with the parent compound was resolved with high-resolution mass measurements determined using a quadrupole-time-of-flight mass spectrometer (Q-TOF). The accurate mass of the observed peak was 0.0362 amu lower than the parent compound and correlated to the formation of a carboxylic acid moiety (RCOOH) via demethylation and subsequent oxidation. 

S. L. Evarts, T. C. Webb, and M. T. Cancilla, A dual stream LC ESI quadrupole-time-of-flight mass spectrometer to double the throughput of intact protein and peptide digest analyses, in 52nd ASMS Conference on Mass Spectrometry and Allied Topics, Nashville, TN (Book of Abstracts), 2004. 

Spectrometry having an applied DC charge and alternative voltage applied (Herbert, C.G. and Johnstone, R.A.W., Mass Spectrometry Basics, CRC Press, Boca Raton, EL, Chapter 25, 2003). These instruments are generally referred to as quadrupole/time-of-flight mass spectrometers. See Homing, E.C., Carroll, D.I., Dzidic, I. et al.. Development and use of analytical systems based on mass spectrometry, Clin. Chem. 23, 13-21,1977 Yost, R.A. and... 

Ekroos K, Chernushevich IV, Simons K, Shevchenko A. Quantitative profiling of phospholipids by multiple precursor ion scanning on a hybrid quadrupole time-of-flight mass spectrometer. Anal Chem. 2002 74 941-949. 

Since 2002, on-line nanoscale LC-ESI-MS/MS was used for the analysis of the peptidome of. Drosophila samples. This combination greatly improves the sensitivity of detection. Starting from only 50 larval Drosophila CNS, 28 peptides were isolated and sequenced in an on-line quadrupole time-of-flight mass spectrometer [27]. Later, two-dimensional capillary LC-ESI-MS/MS has enhanced the coverage of this peptidomics analysis with the identification of twenty additional peptides [31]. The CNS extract has been first fractionated onto a strong cation-exchange column then onto a reversed-phase column before ESI-MS/MS analysis. Recently this approach has been applied to Drosophila larvae hemolymph to identify new peptides induced by a septic injury [22]. Most of the identified molecules correspond to truncated forms or propeptides of known AMPs and DIMs [15,20,21], but two previously unknown peptide precursors, potentially involved in the innate immune response, have been also detected by this way. 

It is of interest to mention some detailed mass spectrometric results that were obtained by performing distinct experiments (a) ion-molecule reactions in mixtures of haloben-zenes and ammonia under chemical ionization conditions (b) ion-molecule reactions of mass-selected ionized halobenzenes toward ammonia in a quadrupole collision cell of a hybrid tandem mass spectrometer (c) ion-molecule reactions of phenyl diazonium cations with ammonia in the same quadrupole collision cell and, finally, (d) electrospray ionization of anilines in a hybrid quadrupole-time of flight mass spectrometer (QTof). Characterization of the product ions relies on collisional activation experiments in the low or high kinetic energy regime98. 

Li, J., Wang, C., Kelly, J. E, Harrison, D. J., and Thibault, P. Rapid and sensitive separation of trace level protein digests using microfabricated devices coupled to a quadrupole-time-of-flight mass spectrometer. Electrophoresis 21 198-210, 2000. 

J.M. Ginter, E Zhou and M.V. Johnston, Generating protein sequence tags by combining cone and conventional collision induced dissociation in a quadrupole time-of-flight mass spectrometer. Journal of the American Society for Mass Spectrometry, 15, 1478-1486 (2004). 

FIGURE 4.5 Continued, (d) ESI quadrupole time-of-flight mass spectrometer and (e) ESI Fourier transform ion cyclotron mass spectrometer. CID = collision-induced dissociation, Q = quadrupole mass analyzer, q = RE only ion guide, D = detector, P = pusher electrode, MSI = first stage of mass spectrometry, MS2 = second stage of mass spectrometry, and PSD =... 

Hop, C.E.C.A. et al., Elucidation of fragmentation mechanisms involving transfer of three hydrogen atoms using a quadrupole time-of-flight mass spectrometer, J. Mass Spectrom., 36, 575, 2001. 

The hybrid quadrupole time of flight mass spectrometer (QTOF) was introduced as a mass spectrometer capable of tandem MS with particular emphasis on its applicability for protein and peptide analysis. It combines the simplicity of a quadmpole MS with the high efficiency of a... 

Gomez-Ariza, J.L., Arias-Borrego, A., Garcia-Barrera, T., and Beltran, R., Comparative study of electrospray ionization sources coupled to quadrupole time-of-flight mass spectrometer for olive oil authentication, Talanta, 70, 859-869, 2006. 

MS coupled with a quadrupole time-of-flight mass spectrometer operated as a straight TOF mass analyzer in full-scan mode... 

---