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Emerging Biomedical Analysis
Published in Lawrence S. Chan, William C. Tang, Engineering-Medicine, 2019
Ion trap analyzers: Ion traps (IT) are built based on the same mechanism as the quadrupole mass filter. Instead of continuously passing ions through the quadrupole, ion traps are designed with ring electrodes (in a 3D ion trap) or a two-dimensional quadrupole field (in a linear ion trap) to trap and eject ions sequentially.
Mass Spectrometry Instrumentation
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Yuan Su, Li-Rong Yu, Thomas P. Conrads, Timothy D. Veenstra
Compared with FTICR, Orbitrap can offer a similarly high resolution (104–106) and high mass accuracy (1–5 ppm) but requires less regular operational maintenance. In addition, since a linear ion trap can provide very highly sensitive mass detection, multiple-stage tandem mass spectrometry (MSn), and compatible scan speed for the LC-MS detection of peptides, the combination of the Orbitrap mass analyzer with a linear ion trap allows both MS and MS/MS spectra to be recorded by using either the ion trap, for high speed and sensitivity, or Orbitrap, for high resolution and accuracy. The full use of each analyzer’s performance led to the rapid commercialization of this hybrid instrument as a high-end mass spectrometer for proteomic analysis (Eliuk and Makarov, 2015). Moreover, the Orbitrap Elite mass spectrometer from Thermo Fisher Scientific also implements additional fragmentation techniques, including a new multipole for higher-energy collision-induced dissociation (HCD) and an electron transfer dissociation (ETD) reagent ion source, to obtain more structural information than can be provided by low-energy CID fragmentation. HCD fragmentation is a beam-type collisional dissociation that occurs in a gas-filled quadrupole directly after the C-trap. The collision energy of ions is initiated by adjusting the DC offset on the rod electrodes in the same way as in a conventional collision cell (Olsen et al., 2007). ETD is a fragmentation technique that dissociates the peptide backbone, leaving the post-translational modifications (PTMs) intact (Syka et al., 2004). The combination of ETD with CID not only makes the sequence coverage of proteins and peptides more complete but also improves the identification and localization of PTMs (Li et al., 2014). However, the filament-based ETD ionization source makes high demands on tuning and maintenance. Orbitrap Fusion, an updated version of Orbitrap, uses Townsend discharge to ionize the ETD reagent, which significantly reduces the maintenance work (Earley et al., 2013). The dual-pressure ion-trap mass analyzer and S-lens technology also accelerate acquisition rates and improve the system sensitivity (Olsen et al., 2009) (Figure 14.12).
Genotoxicity of quinone: An insight on DNA adducts and its LC-MS-based detection
Published in Critical Reviews in Environmental Science and Technology, 2022
Yue Xiong, Han Yeong Kaw, Lizhong Zhu, Wei Wang
The configuration of ion trap (IT) mass spectrometers includes quadrupole ion traps (QIT) and linear ion traps (LIT) which use dynamic electric fields to trap charged particles (Clarke, 2017). In light of the sensitivity and selectivity, ITs can be performed in multistage MS experiments (MSn) and tandem mass spectrometry, which reflect both the excellent qualitative and quantitative abilities of ITs. Yun et al. utilized LIT in MS3 scan stage to characterize the structure of 7-(deoxyadenosin-N6-yl) aristolactam I in formalin-fixed paraffin embedded (FFPE) kidney and liver tissues with the LOD of 0.15 adducts/108 nucleosides (Yun et al., 2015). Recently, hybrid triple quadrupole-linear ion trap (QTrap) MS system is commonly used for detecting DNA adducts. When fragment ions were produced by CID from Q1 to Q2, they can be trapped within the LIT region and sequentially ejected, producing a full mass spectrum without significant loss of sensitivity (Tang & Zhang, 2020). Wang et al. developed a UHPLC-ESI-QTrap method to detect sulfur mustard-induced N3-HETEA, N7-HETEG and Bis-G in human cell and rat tissues, which achieved the LODs of 0.02, 0.1 and 0.05 ng/mL, respectively. (Wang et al., 2015).
On the product selectivity in the electrochemical reductive cleavage of 2-phenoxyacetophenone, a lignin model compound
Published in Green Chemistry Letters and Reviews, 2022
Marcia Gabriely A. da Cruz, Bruno V. M. Rodrigues, Andjelka Ristic, Serhiy Budnyk, Shoubhik Das, Adam Slabon
GC-MS samples were dissolved in a methanol–chloroform mixture (volumetric ratio 3:7, dilution factor of 1:1000). Sample solutions were then introduced into a LTQ Orbitrap XL hybrid tandem high-resolution mass spectrometer from Thermo Fisher Scientific (Bremen, Germany) by direct infusion applying a flow rate of 5 µL/min. The instrument was fitted with electrospray ionization (ESI) ion source and operated in positive or negative ion mode respectively. Nitrogen was used as sheath gas. Helium was used both as buffer and collision gas in the linear ion trap section where lower energy collision-induced dissociation (CID) was performed. For the identification of chemical structures by tandem MS, product ions were generated in the linear ion trap via CID and detected by the high-resolution orbitrap section of the instrument at a resolution of 60,000 (full width at half maximum, FWHM). The mass measurements were acquired with a mass accuracy of 5 ppm or better. Data processing and interpretation were done using the software tools Xcalibur version 2.0.7 and Mass Frontier version 6.0 from Thermo Fisher Scientific (Bremen, Germany). m/z describes the mass-to-charge ratio of the detected ions. As all negatively charged ions analyzed were single charged species, m/z also referred to the monoisotopic molecular masses of the detected ions. It is noted that ionization capability of chemical compounds is dependent on the chemical structure. Thus, for spectrum interpretation, especially of the different depolymerization routes and model products, the intensities detected can only be compared between the same species found in the analyzed samples obtained by the similar procedure but not between different species.
Solvent-free synthesis of photoluminescent carbon nanoparticles from lignin-derived monomers as feedstock
Published in Green Chemistry Letters and Reviews, 2023
Márcia G. A. da Cruz, Joy N. Onwumere, Jianhong Chen, Björn Beele, Maksym Yarema, Serhiy Budnyk, Adam Slabon, Bruno V. M. Rodrigues
Direct injection high-resolution MS samples were dissolved in a chloroform/methanol mixture (3:7, dilution factor of 1:1000). Samples were introduced into a LTQ Orbitrap XL hybrid tandem high-resolution MS from Thermo Fisher Scientific (Bremen, Germany) by direct infusion applying a flow rate of 5 μL min−1. The instrument was fitted with electrospray ionization (ESI) ion source and operated in positive or negative ion mode. Nitrogen was used as a sheath gas. Helium was used both as a buffer and a collision gas in the linear ion trap section, where lower energy collision-induced dissociation (CID) was performed. For the identification of chemical structures by tandem MS, product ions were generated in the linear ion trap via CID and detected by the high-resolution orbitrap section of the instrument at a resolution of 60,000 (full width at half maximum, FWHM). The mass measurements were acquired with a mass accuracy of 5 ppm or better. Data processing and interpretation were performed using the software tools Xcalibur version 2.0.7 and Mass Frontier version 6.0 from Thermo Fisher Scientific (Bremen, Germany). m/z describes the mass-to-charge ratio of the detected ions. As all negatively charged ions analyzed were single-charged species, m/z also referred to the monoisotopic molecular masses of the detected ions. It is noted that ionization capability of chemical compounds is dependent on the chemical structure. Fourier-transform infrared spectroscopy (FT-IR) analysis was carried out using a Varian 610-IR FT-IR spectrometer. The samples were analyzed at room temperature in ATR mode, in the range of 400–4000 cm−1, with 16 scans at 4 cm−1 resolution and 1 cm−1 interval. The 1H NMR spectra of samples were recorded using a Bruker Avance III 600 MHz instrument (νL, 1H = 600.13 MHz) in 5 mm NMR tubes at 300 K. Chemical shifts are given relative to Me4Si. TEM micrographs were obtained using a JEOL 2100F microscope. The optical properties were evaluated using a UV-3100PC spectrophotometer (VWR, USA) and a Varian Cary Fluorescence spectrometer (SPECTRFluor).