Thermo LTQ

Figure 2.19 Thermo LTQ-FT mass spectrometer. Reprinted from Ref. [112] with permission from Elsevier.

Analyses have been performed on a Thermo LTQ Orbitrap eqiripped with a Prosolia s Omni Spray DESI ion somce, used as a nano ES source. The instrument was operated in full-scan mode (60,000 resolution) and in MS/MS mode (30,000 resolution), to confirm drag identities. 

The LCQ, LCQ DECA, and LTQ are products of Thermo Electron corporation (San Jose, CA), and the QSTAR is a product of Applied Biosystems (Foster City, CA). 

FIGURE 5.2 Ion path for LTQ-Orbitrap. (Courtesy of Thermo Fisher Scientific, Waltham, Massachusetts.)... 

Due to the limited peak capacity of the 15 cm analytical column utilized in 2-D nano LC-MS, several elution steps are required to achieve the required separation. The 15 cm analytical column can be replaced with a 100 cm nano LC column to increase the resolution of sample in each step. As shown by Yang,20 a 100 cm column allows the one-step separation of more than 2000 polypeptides from trypsin digest of mouse brain lysate, P2 fraction using XtremeSimple ultrahigh pressure nano LC (Micro-Tech Scientific, Vista, California) and LTQ MS (Thermo Electron, San Jose, California) in 6 hr (Figure 14.16). In addition to the improvement of resolving power with a 100 cm column, it... 

FIGURE 14.17 Ultrahigh resolution nano LC-MS separation of base peak chromatogram of 2351 peptides identified in trypsin digest of mouse brain lysate P2 fraction using Micro-Tech XtremeSimple nano-LC and Thermo Electron LTQ. Column 100 cm x 75 fim C18 column, 3 /mi, 8000 psi column head pressure. Solvent composition time 350 min gradient, 5 to 35% B. Solvent A 2% acetonitrile, 0.1% formic acid. Solvent B 95% acetonitrile, 0.1% formic acid. Data analysis Sequest, PeptideProphet, and Protein Prophet. 

LITs capable of scanning, axial or radial excitation of ions, and precursor ion selection for MS/MS experiments [118,134-136] have lately been incorporated in commercial mass spectrometers (Fig. 4.39). The replacement of Q3 in a QqQ instrument with a scanning LIT, for example, enhances its sensitivity and offers new modes of operation (Applied Biosystems Q-Trap). Introduction of a scanning LIT [118,135] as MSI in front of an FT-ICR instrument (Thermo Electron LTQ-FT) shields the ultrahigh vacuum of the FT-ICR from collision gas and decomposition products in order to operate under optimum conditions. In addition, the LIT accumulates and eventually mass-selects ions for the next cycle while the ICR cell is still busy with the previous ion package. 

The next higher level of performance can be achieved by replacing the oaTOF MS2 with an FT-ICR analyzer while employing a linear ion trap (Thermo Electron LTQ-FT) or a quadmpole as MSI (Bruker Daltonik APEX-Q). 

Fig. 1.30 Schematic of the linear ion trap (LIT)-orbitrap (LTQ orbitrap, Thermo). One of the specificities of the system is that the LIT has two detectors. Therefore the LIT can perform various experiments at the same time. Adapted with permission from reference [76].

Figure 4.1 Separation of H3 9-17 trimethylated subsequentlydigested with trypsin. The resulting at l<9 from H3 9-17 monoacetylated. Histone peptides were analyzed by LC-MS/MSemploying H3 isolated from Drosophila melanogaster was LTQ-Orbitrap (Thermo Scientific) as detector, acylated with deuterated acetic anhydride and (a) Chromatogram of the analysis. The y axis...

FT-ICR-MS systems equipped with external API sources are conunercially available from Bruker Instruments, lonSpec, and Thermo Fimiigan. In order to control the number of ions in the ICR cell, hybrid systems have been developed. Bruker offers a FT-ICR-MS hybrid with a quadrapole front-end (APEX-Qh) [121], whereas the LTQ-FT instrument from Thermo Fimiigan features a linear-ion-trap (LIT, Ch. 2.4.2) front end [122]. In this way, MS-MS can be performed prior to ion introduction into the ICR-cell, avoiding problems with CID in the ICR-cell. 

An LTQ linear ion trap tandem mass spectrometer (Thermo Finnigan Corp, San Jose, CA) is routinely used in our laboratory. XCalibur Software is used to automate the acquisition of tandem mass spectra over a 400-1600-m/z range and to control precursor ion selection by the instrument in a data-dependent, data-acquisition mode, with dynamic exclusion activated. 

FIGURE 8.5 FAIMS spectrum of loperamide in the presence of polyethylene glycol. The resolving power of this spectrum is about 4. (From Homer and Phillips, The nse of FAIMS to separate loperamide from PEG prior to ms analysis using an LTQ XL, Thermo Fisher Scientific Application Notes 2008, Application Note 395. With permission.)... 

Thermo Scientific has introduced the 2D (or linear) liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/ MS/MS) ion trap mass spectrometer [11], known as the LTQ. The ion injection efficiency has been improved dramatically in the linear ion trap. In addition, ions in a linear ion trap are distributed along the central axis, rather than concentrated in the ion trap center for a 3D ion trap thus, both charge capacity and sensitivity in a linear ion trap have been increased significantly. Although at the present time there is neither commercial linear ion trap/GC/MS nor commercial linear ion trap/GC/ MS/MS instruments, a commercial version of a linear ion trap/GC/MS is expected to appear in the near future. 

Figure 2.6 Shotgun steroidomic analysis of infant plasma. Steroids were isolated from infant plasma by SPE on a Qg cartridge. Direct negative-ion ESI-MS analysis was performed on an LTQ Orbitrap XL (Thermo Fisher). Peaks which correspond to steroid sulphates are indicated. Steroid structures (see Figure 2.7) are postulated but have not been confirmed. (A) Androstane. (p) Pregnane, location of double bonds indicated by a superscript.

Huang Y, Liu S, Miao S, Jeanville PM. Using multiple mass defect filters and higher energy collisional dissociation on an LTQ Orbitrap XL for fast, sensitive, and accurate metabolite ID, 2008, available www.thermo.com/appnotes. 

FIGURE 13.3 Instrument schematics for (a), Waters Synapt QTOF ( Waters), (b) Thermo Finnigan LTQ-Orbitrap, and (c) Thermo Finnegan LTQ FTICR mass spectrometers ( Thermo Finnegan). 

The Thermo Scientific ion source can be retrofitted to the LTQ Orbitrap XL line of instruments, while the TransMIT ion source can be retrofitted to the Exactive series instrumentation. The MassTech AP MALDI PDF+ ion source has also been adapted to both hybrid Orbitrap devices, as well as to bench-top Orbitrap systems. 

Figure 4.12 MALDI-MSI of a mouse kidney tissue section after treatment of the animal with imatinib, obtained with a high-resolution AP-SMALDI imaging ion source on a LTQ Orbitrap Discovery mass spectrometer (Thermo Fisher Scientific GmbH, Bremen, Germany), (a) Overlay of selected phospholipid ion images representing distinct tissue areas cortex, green, [PC(32 0)-fK] at m/z = 772.5253 outer stripe outer medulla, blue, [PC(40 6)-fK]+ at m/z = 872.5566 inner stripe outer medulla, red, [PC(38 5)-fK] at...

MS, MS/MS and MS experiments were performed with a LTQ-Orbitrap (Thermo Fisher Scientific Inc., San Jose, CA, USA) mass spectrometer equipped with a Triversa Nanomate (Advion Biosciences Inc., Ithaca, NY, USA). Compound solutions were infused with a nanospray chip. The mass spectrometer was first calibrated externally with a mixture containing caffeine, L-methionyl-arginyl-phenylalanyl-alanine (MRFA) and Ultramark 1621 in ACN, MeOH, HjO, acetic acid. Sub-ppm mass accuracy was finally achieved using an internal calibration (lock mass) in both MS and MS/MS mode. The resolution of Orbitrap MS was set to 100,000 (FWHM) at m/z 400. Electrospray ionization (ESI) was used. For MS/MS experiments, an isolation width of 1.5 Da was used. The normalized collision energy was set to the value when the precursor ion was exhausted. Helium was used as the collision gas. 

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