Hybrid instruments Orbitrap

Some mass spectrometers combine several types of analysers. The most common ones include two or more of the following analysers electromagnetic with configurations EB or BE, quadrupoles (Q), ion traps (ITs) with Paul ion traps or linear ion traps (LITs), time-of-flight (TOF), ion cyclotron resonance (ICR) or orbitrap (OT). These are named hybrid instruments. The aim of a hybrid instrument is to combine the strengths of each analyser while avoiding the combination of their weaknesses. Thus, better performances are obtained with a hybrid instrument than with isolated analysers. Hybrids are symbolized by combinations of the abbreviations indicated in the order that the ions travel through the analysers. 

An IT analyser has also been coupled to an ICR FTMS instrument, yielding a hybrid instrument in the IT ICR configuration. This hybrid instrument gives high sensitivity at the attomole level, a high resolution of 100000FWHM at 1 s scan rate and a high mass accuracy of 1 to 2 ppm with external calibration at 1 scan per second. A similar hybrid instrument in which the ICR analyser is replaced by an orbitrap analyser has also been... 

ToF analyzers as well as hybrid instruments that combine two or more mass-resolving components, such as quadrupole-ToF (Q-ToF), ion-mobility ToF, and ion-trap-ToF, as well as the high-resolving Fourier transform (FT) analyzer Orbitrap and ion cyclotron resonance (ICR). For targeted analysis, a multiple-reaction monitoring instrument based on triple-quadrupole technologies (QQQ) has provided unrivaled sensitivity for MSI of pharmaceuticals, yet its targeted nature renders it unsuitable for discovery-based research. 

Various hybrid tandem mass spectrometers, which combine two or more distinct types of mass analyzers, have been developed to maximize analytical performance and functionality. From the standpoint of ion/ion reactions, the incorporation of an electrodynamic ion trap into a hybrid instrument allows for the physical separation of the three basic steps involved in an ion/ion reaction experiment, that is, ionization, ion/ion reaction, and mass analysis of reaction products. The separation of these processes provides for the highest degree of flexibility and minimal compromises in the optimization of each step. To date, three major types of hybrid instrnments have been described for ion/ion reaction studies using an electrodynamic ion trap as the reaction vessel. The three major types of hybrid instruments are (i) quadrupole/TOF tandem mass spectrometer (ii) Orbitrap and (iii) LIT /FT-ICR. 

Imaging of Similar Mass Neuropeptides in Neuronal Tissue by Enhanced Resolution MALDI MS with an Ion Trap -Orbitrap Hybrid Instrument... 

It is clear that mass spectrometry imaging has great potential as a comprehensive analysis technique for endogenous peptides, particularly with a hardware configuration as evaluated in this chapter, where MALDI produced ions are analyzed in an ion trap - Orbitrap hybrid instrumentation. A single experiment can provide high mass accuracy data in combination with the spatial distribution of peptides in the tissue sample. With MS/MS experiments the molecular identity (accurate mass measurements complemented with MS" sequence data) can be confirmed firom a single or few scans only and from a few laser shots in total. 

Ions in Orbitrap are electrostatically trapped in an orbit around a central, spindle shaped electrode [73]. The electrode confines the ions so that they orbit around the central electrode and also oscillate back and forth along the central electrode s long axis. This oscillation generates image currents, the frequencies of which depend on the mass-to-charge ratios of the ions. Mass spectra are obtained by Fourier transformation of the recorded image currents. Some of the figures of merit of the Orbitrap in the hybrid instruments such as LIT-Orbitrap or Qq-Orbitrap are as follows ... 

High Mass Accuracy-Based Shotgun Lipidomics Currently, commercially available hybrid instruments (e.g., quadrupole-time-of-flight (Q-TOF) or Q-Exactive (i.e., quadrupole-Orbitrap) mass spectrometers) offer an improved duty cycle that increases the detection sensitivity and/or high mass resolution/accuracy [18, 19]. These instruments can thus be employed to quickly perform product-ion... 

As anticipated in the sections on linear ion traps (Chap. 4.4.6), modem Fourier transform-ion cyclotron resonance (Chap. 4.7.11), and LIT-orbitrap mass spectrometers (Chap. 4.8.4), our instrumeaitation may efficiently be constructed by combining different types of mass analyzers and ion-gitiding devices in a single so-called hybrid instrument [219,220]. The driving force to do so is the desire to obtain mass spectrometers that unite the advantageous properties of each mass... 

Fig. 4.68. Schematic of a LIT-FT-ICR hybrid instrument, the Thermo Scientific LTQ FT Ultra, incorporating a fully functional LTQ front end (as in LTQ Orbitrap) for highest versatility. Courtesy of Thermo Fisher Scientific, Bremen.

It makes sense to extend the HCD geometry towards the dual-LIT MSI to arrive at an advanced hybrid instrument design that combines MS in several modes with a powerful final m/z analysis [121]. Such an instrument has become available in the form of the Thermo Scientific LTQ Orbitrap Velos (Fig. 9.27). One of the most important advantages of this instrumentation is speed for proteomics analysis, e.g., within 1.0 s the dual-LIT can deliver five complete tandem mass spectra simultaneously with the orbitrap running one high-resolution accurate mass scan of the whole m/z range. 

Fig. 9.26. Schematic of the hybrid LIT-orbitrap instrument indicating the electrostatic potentials used in HCD and comparison of QD spectra, (a) HCD operation of the C-trap (b) with octopole collision ceU (c) CID spectrum of peptide [HLVDEPQNLIK+2H] ions from HCD as in (a) (d) spectrum as obtained by setup (b). NL intensity in counts normalized to 1 s TIC total ion current. Reproduced from Ref. [123] with permission. Nature Publishing Group, London, 2007.

Combination of two different mass spectrometer types in so-called hybrid instruments such as linear ion trap/orbitrap (LTQ-Orbitrap) has shown excellent detection and identification capabilities for low molecular weight compounds in various... 

With recent instrumental development, such as fast LC, fast GC and two-dimensional gas chromatography (GCxGC) and advanced tandem hybrid MS detection systems (i.e., QqTOF, QqLIT, Orbitrap) the analysis of complex mixtures... 

Orbitrap The newest of the major mass analyzers, the Orbitrap is a hybrid MS consisting of a LIT mass analyzer, or transmission quadmpoles connected to the high-resolution Orbitrap mass analyzer. The Orbitrap utilizes electrical fields between sections of a roughly egg-shaped outer electrode and an inner (spindle) electrode (Chapter 5). Ions orbit between the inner and outer electrodes and their oscillation is recorded on detector plates (Hardman and Makarov, 2003 Hu et al., 2005). As with the FTICR, fast Fourier transform of the raw data is used to convert the data for mass analysis, making the Orbitrap the second major type of FTMS instrument. The resolving power of the Orbitrap is intermediate... 

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