Mass spectrometry hybrid instruments

In mass spectrometers, ions are analysed according to the ml7. (mass-to-charge) value and not to the mass. While there are many possible combinations of technologies associated with a mass-spectrometry experiment, relatively few forms of mass analysis predominate. They include linear multipoles, such as the quadrupole mass filter, time-of-flight mass spectrometry, ion trapping forms of mass spectrometry, including the quadrupole ion trap and Fourier-transform ion-cyclotron resonance, and sector mass spectrometry. Hybrid instruments intend to combine the strengths of the component analysers. 

Musharraf SG, Ali A, Ali RA, Yousuf S, Atta-ur-Rahman, Choudhary MI (2011) Analysis and development of structure-fragmentation relationship in withanolides using an electrospray ionization quadrapole time of flight tandem mass spectrometry hybrid instrument. Rapid Commun Mass Spectrom 25 104—114... 

In most designs secondary neutral mass spectrometry (SNMS) instruments are to a large extent identical with SIMS instruments so there are usually hybrids that work... 

Instrumental developments concern micro ion traps (sub-mm i.d.) [193], extension of the mass range, mass resolution and capture efficiency for ions generated externally. Fast separations at very low detection levels are possible by means of hybrid QIT/reToF mass spectrometry [194]. 

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. 

The techniques developed to study protein interactions can be divided into a number of major categories (Table 31.1), including bioconjugation, protein interaction mapping, affinity capture, two-hybrid techniques, protein probing, and instrumental analysis (i.e., NMR, crystallography, mass spectrometry, and surface plasmon resonance). Many of these methods are dependent on the use of an initial bioconjugation step to discern key information on protein interaction partners. 

Further improvements in retrospectivity and detection limits will hinge on future enhancements of sensitivity and resolution of electro-spray mass spectrometry instruments and of several hybrid configurations. 

TOF analyzers are especially compatible with MALDI ion sources and hence are frequently coupled in aMALDI-TOF configuration. Nevertheless, many commercial mass spectrometers combine ESI with TOF with great success. For proteomics applications, the quadrupole TOF (QqTOF) hybrid instruments with their superior mass accuracy, mass range, and mass resolution are of much greater utility than simple TOF instruments.21,22 Moreover, TOF instruments feature high sensitivity because they can generate full scan data without the necessity for scanning that causes ion loss and decreased sensitivity. Linear mode TOF instruments cannot perform tandem mass spectrometry. This problem is addressed by hybrid instruments that incorporate analyzers with mass selective capability (e.g., QqTOF) in front of a TOF instrument. 

The majority of H/D studies that have been reported employ quadrupole ion trap (QIT) instruments due to their ease of use, excellent sensitivity, ability to perform MS/MS experiments, compact size, and low cost. Other reports discuss the use of instruments with higher mass-resolving power such as the hybrid QqTOF instruments [47]. A few groups have utilized FT-ICR mass spectrometry, which offers ultra-high mass-resolving power and improved mass accuracy [48, 49]. 

Finally, it is important to note there are many other instruments and configurations that are often referred to as tandem mass spectrometers. There are hybrid instruments that use another form of mass separation, time-of-flight (TOF) mass spectrometry. TOF mass spectrometry separates ions based on the time it takes to... 

Sanders, M., Warrack, B., Lange, O., Strupat, K., and Homing, S. (2005). Optimizing low mass ion transmission on a hybrid linear ion trap FTICR-MS instrument and its application to metabonomic profiling, In Proceedings of the 53rd ASMS Conference on Mass Spectrometry and Allied Topics, San Antonio, TX. 

Yost, R. A. Boyd, R. K. 1990. Tandem mass spectrometry quadrupole and hybrid instruments. Methods Enzymol., 193,154-200. 

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. 

Many instrumental set-ups and geometries have been explored. In triple quadrupole mass spectrometry, the first quadrupole selects the parent ion of interest, the second works as a collision cell to fragment the parent ion, and the third isolates the proper product ion. A hybrid type is the quadrupole time-of-flight (Q-TOF) instrument. 

Boyd, R.K., Tandem mass spectrometry quadropole and hybrid instruments, Metftodi nzymo/. 193, 154-200, 1990 Jonscher, K.R. and Yates, J.R., 111, The quadrupole ion trap mass spectrometry — a small solution to a big challenge. Anal. Biochem. 244, 1-15, 1997 Chemushevich, I.V., Loboda, A.V., and Thomson, B.A., An introduction to quadrupole-time-of-flight mass spectrometry, J. Mass Spectrom. 36, 849-865, 2001 Ens, W. and Standing, K.G., Hybrid quadrapole/time-of-flight mass spectrometers for analysis of biomolecules. Methods Enzymol. 402,49-78, 2005 Payne, A.H. and GUsh, G.L., Tandem mass spectrometry in quadrupole ion trap and ion cyclotron resonance mass spectrometers. Methods Enzymol. 402, 109-148, 2005. 

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