Ion trap mass spectrometer, ITMS

The commercial ion trap mass spectrometer (ITMS) can be an economical solution for detection of multiple targeted compounds however, repetition rate is relatively slow especially for MS/MS mode. 

GC analysis is performed by using an ion trap mass spectrometer (ITMS) equipped with a chemical liquid ionization system. Figure 6.4 shows the GC-MS chromatogram relative to THPI and captan analysis in a grape sample, analytical conditions are reported in Table 6.13. The... 

The more universal and less sensitive flame-ionization detector (EID) is used much less often than the electron capture detector (ECD), which has exceptional sensitivity to multiply chlorinated compounds. The mass spectrometer-selected-ion-monitoring (MS-SIM) or ion-trap mass spectrometer (ITMS)... 

The RF quadrupole ion trap mass spectrometer (ITMS) is a close relative of the QMF and ideally can be thought of as a three-dimensional quadrupole (see Fig. 17.8). The close relationship of these two devices is evident by the fact that ion motion in the two devices is governed by essentially the same mathematical equations. As with the QMF, the ITMS uses DC and RF electric fields and the operation of the IT is described by solutions to the Mathieu equation. Unlike the QMF, ITMS analyzers trap ions within the mass analyzer. Ions are trapped, ejected to select the mass of interest, and then ejected in a controlled manner for detection. 

For the ion source and the mass spectrometer, atmospheric pressure chemical ionization (APCI) with an ion trap mass spectrometer (ITMS) is mainly used. The ion source and the mass spectrometer used in our laboratory for detection of explosives are described below. 

The instrument used in these analyses was a modified version of the Finnigan ion trap mass spectrometer (ITMS) running ICMS software and coupled with a Teledyne HST-1000 filtered noise field system. The end caps of the IT were modified with larger apertures (5 mm) that were covered with spot-welded 90% pass grids. The instrument was operated in the negative-ion mode. 

G.C. Stafford, The Finnigan MAT Ion Trap Mass Spectrometer (ITMS) - New Developments with Ion Technology, Finnegan MAT IDT Publication 24. 

Volatile analysis of foods is used to determine various properties including quality, purity, origin, and composition. Due to the relatively low concentrations of volatile materials that can affect the acceptance or rejection of a food, a procedure is normally employed to extract and concentrate the sample sufficiently prior to instrumental analysis. The predominant method for analyzing volatiles is gas chromatography (GC). Typically, compounds need to be delivered to the head of the GC column in the nanogram range in order to be detected. However, specialized detectors such as ion trap mass spectrometers (ITMS) or sulfur chemilu-... 

GC = gas chromatography ECD = electron capture detector EIA = enzyme-immunoassay GPC = gel permeation chromatography HPLC = high-performance liquid chromatography ITMS = ion trap mass spectrometer LSE = liquid solid extraction MS = mass spectrometry RSD = relative standard deviation SPE = solid phase extraction... 

The film reactor-ion trap mass spectrometer technique (FR-ITMS) introduced in this paper offers the potential for novel dynamic investigations of the Maillard reaction. Application of the technique to a glucose/leucine system has shown reactants, intermediates and end products to be successfully monitored in short time scales under rapidly changing reaction environments. 

The major drawbacks to using an external ion source was related to the complexity of operation in switching from El to Cl in contrast to the usual configuration, and the requirement for an additional vacuum system. Nevertheless, external ion source GC/ITMS is undergoing commercial development, and manufacturers currently provide external ion source designs for the new generations of ion-trap mass spectrometers. 

Ltti, H. K. Wu, W-N. Mordehai, A. Henion, J. D. Determination of quaternary isoquinoline alkaloids by ion spray ion trap mass spectrometer (IS/ITMS). In Proceedings of the 41st Conference on Mass Spectrometry and Allied Topics,... 

Multiple mass analyzers exist that can perform tandem mass spectrometry. Some use a tandem-in-space configuration, such as the triple quadrupole mass analyzers illustrated (Fig.3.9). Others use a tandem-in-time configuration and include instruments such as ion-traps (ITMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS or FTMS). A triple quadrupole mass spectrometer can only perform the tandem process once for an isolated precursor ion (e.g., MS/MS), but trapping or tandem-in-time instruments can perform repetitive tandem mass spectrometry (MS ), thus adding n 1 degrees of structural characterization and elucidation. When an ion-trap is combined with HPLC and photodiode array detection, the net result is a profiling tool that is a powerful tool for both metabolite profiling and metabolite identification. 

Various mass spectrometers such as a single quadrupole, triple quadrupole, and quadrupole ITMSs are used for the detection of explosives. However, the ITMS has several advantages for homeland security applications. For example, the quadrupole ion trap has high sensitivity with a full scan mode and has tandem mass spectrometry (MS/MS) capabilities. Furthermore, the quadrupole ion trap is robust, and complicated calibrations are not necessary with this instrument format. 

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