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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
Among different types of ion trap, the quadrupole ion trap is one of the most popular mass analyzers for proteomic analysis. The popularity of the quadrupole ion trap has its roots in the discovery and development of the mass-selective axial instability scan (Stafford et al., 1984). The first development was the mass-selective instability mode of operation, in which the ions created over a given period could be trapped and then sequentially ejected into a conventional electron multiplier detector. Unlike the mass-selective stability mode of operation, in which only one m/z value could be stored, ions with a wide range of m/z values could be stored. The next major development showed that the mass resolution of this mass analyzer could be improved by adding about 1 mTorr of helium gas to the ion trap. This increase in resolution is because of a reduction of the kinetic energy of the ions and the contraction of their trajectories to the center of the trap (Stafford et al., 1984). This contraction allows packets of ions of a given m/z to form, enabling them to be ejected faster and more efficiently than a diffuse cloud of ions, thereby improving resolution and sensitivity.
Mass Spectrometers
Published in Béla G. Lipták, Analytical Instrumentation, 2018
The quadrupole ion trap is a mass spectrometer that has a broad mass range, provides molecular weight and structural information on biopolymers, and has the greatest sensitivity of all mass spectrometers. The instrument employs three electrodes—two end cap electrodes that normally are at ground potential and between them a ring electrode to which a radio frequency (RF) voltage, often in the megaHertz range, is applied—to generate a quadrupole electric field (Figure 28f). The ions that undergo stable oscillations and are trapped under a given set of operating conditions may be analyzed by several methods.
Detection Technology
Published in Rick Houghton, William Bennett, Emergency Characterization of Unknown Materials, 2020
Rick Houghton, William Bennett
The quadrupole ion trap mass analyzer is similar to the quadrupole mass analyzer, except the ions are held and selectively ejected as the radio frequency potential is ramped. Other variations exist for the ion trap. A linear version of the quadrupole trap isolates ions in two dimensions instead of three.
High-resolution vibrational predissociation spectroscopy of I− · H2O by single-mode CW infrared excitation in a 3D cryogenic ion trap
Published in Molecular Physics, 2023
Payten A. Harville, Sean C. Edington, Olivia C. Moss, Meng Huang, Anne B. McCoy, Mark A. Johnson
The cluster ions were generated using an electrospray ion source that transferred 300 K ions into a 3D (Paul) radiofrequency ion trap (C-1251 Quadrupole Ion Trap, Jordan TOF Products) held at 5 K with a closed cycle He cryostat (RDK 415E, Sumitomo Heavy Industries). The overall schematic of the experiment is presented in Figure 2. After exiting the ca. 0.75 mm, 10 cm long capillary, the ions were first stored in an octupole ion trap with a pressure of about 3 mTorr. A packet of ions was then released by pulsing an aperture to send the ions through two RF-only octupole ion guides before entering the Paul trap. Just prior to the injection of the ion packet into the Paul trap, a pulse of He gas was introduced with a solenoid valve (Series 9 Solenoid Valve 009-0181-900, Parker Hannifin General Valve Division). The time profile of the buffer gas pressure in the trap is depicted in Figure 3(a). The ion bunch released from the storage octupole is timed to enter the Paul trap at the peak of the buffer gas pressure (about 15 ms after the valve is triggered to open). After the ions are cooled, they are stored in the Paul trap for about 60 ms until they are ejected into a time-of-flight mass spectrometer that records the distribution of ions held in the trap. Typically, this consists of the cluster distribution depicted in Fig. S1, with n < 3 or so, with the bare ion being the most abundant species.
Evaluation of catalytic deoxygenation of soluble species from a coal using mass spectrometers
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Chi Zhang, Guo-Sheng Li, Xing Fan, Jing Jiang, Feng-Yun Ma, Yun-Peng Zhao, Xian-Yong Wei, Wen-Long Mo, Wei Zhao
A high-resolution linear quadrupole ion trap/Orbitrap MS (LTQ-Orbitrap MS, Thermo-Fisher Scientific, USA) coupled with an ESI ion source under positive ion mode was used in this work. The source voltage was set to 4.0 kV, the capillary temperature to 150°C, the capillary voltage to 35 V and the tube lens voltage offset to 125 V. The sheath and auxiliary gas (nitrogen) flow rate were set to 10 and 7 arbitrary units, respectively. Mass spectra were collected in full-scan mode with a mass range of m/z 50–1000. Thermo Xcalibur Roadmap software, Data Analysis 2.2, was used for peak selection and chemical formula assignment. The signal-to-noise ratio for peak detection was set to 3 and the chemical formula was assigned with a mass tolerance less than 3 ppm. The chemical formulas were limited to a maximum of 50 C, 100 H, 5 N, 10 O, and 2 S atoms.
Comparison of gas chromatography techniques for the analysis of organochlorine pesticides in sediments
Published in Soil and Sediment Contamination: An International Journal, 2020
L. García, C. Muro, I. De La Rosa, O. Amador-Muñoz, M.G. Ponce, M. Borja
The most employed techniques in the determination of OCPs are gas chromatography with electron capture detection (GC-ECD) and mass spectrometer (GC-MS). The high resolution and reduced cost of operation of GC-ECD have promoted its use in several research projects (Bettinetti et al. 2016; Kafilzadeh 2015; Leyva-Morales et al. 2015; Sánchez-Osorio et al. 2017). However, GC-MS is nowadays the most common method for analyzing multiple analytes in solid samples, showing reduced matrix effects and interferences. Currently, new techniques, such as tandem mass spectrometry (GC-MS/MS), triple quadrupole ion trap mass spectrometry (GC-MS/QIT) and mass spectrometry with negative chemical ionization (GC-MS/NCI), have been developed to improve the analysis of OCPs; increasing the sensitivity and selectivity of the analytes (Arias-Loaiza et al. 2018; Pintado-Herrera, González-Mazo, and Lara-Martín 2016; Wang et al. 2017).