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Collision gas cell

Holmes, J.L. Mommers, A.A. Terlouw, J.K. Hop, C.E.C.A. The Mass Spectrometry of Neutral Species Produced From Mass-Selected Ions by Collision and by Charge Exchange. Experiments With Tandem Collision Gas Cells. Int. J. Mass Spectrom. Ion Proc. 1986, 68,249-264. [Pg.66]

With this method, Andersson and Rosen [169] recently investigated the adsorption of hydrogen or deuterium and oxygen on neutral platinum clusters and discovered the catal3dic water formation on the free clusters. Figure 1.30 displays mass spectra obtained with different partial pressures of hydrogen and oxygen in the separate collision gas cells. Panel a in Fig. 1.30 shows a mass spectrum of pure Pt clusters with no reactive gas in the collision cells. The mass spectrum in panel b was sampled after the cluster ions passed reaction cell 1 filled with 0.14 Pa of O2. The additional peaks in the mass spectrum... [Pg.37]

Fig. 1.30. Mass spectra of platinum clusters Ptn before and after reaction with O2 and D2. In the upper mass spectrum (a) no reaction gas was added to the collision gas cells (cf. Fig. 1.29). Spectrum (b) was obtained with 0.14Pa O2 in reaction cell 1 and no gas in reaction cell 2. Spectrum (c) was sampled after the metal cluster beam passed cell 1 with 0.14 Pa O2 and cell 2 with a deuterium pressure of 0.95 Pa. Note that the mass peaks in (c) are slightly broader and exhibit a small shift with respect to mass spectrum (a). This is due to multiple deuterium adsorption onto the platinum clusters which can, however, not be resolved in the mass spectrum [169]... Fig. 1.30. Mass spectra of platinum clusters Ptn before and after reaction with O2 and D2. In the upper mass spectrum (a) no reaction gas was added to the collision gas cells (cf. Fig. 1.29). Spectrum (b) was obtained with 0.14Pa O2 in reaction cell 1 and no gas in reaction cell 2. Spectrum (c) was sampled after the metal cluster beam passed cell 1 with 0.14 Pa O2 and cell 2 with a deuterium pressure of 0.95 Pa. Note that the mass peaks in (c) are slightly broader and exhibit a small shift with respect to mass spectrum (a). This is due to multiple deuterium adsorption onto the platinum clusters which can, however, not be resolved in the mass spectrum [169]...
LIF has been used to study state-selected ion-atom and ion-molecule collisions in gas cells. Ar reactions with N2 and CO were investigated by Leone and colleagnes in the 1980s [13, 14] and that group has... [Pg.799]

Alternatively, ions of any one selected m/z value can be chosen by holding the magnetic field steady at the correct strength required to pass only the desired ions any other ions are lost to the walls of the instrument. The selected ions pass through the gas cell and are detected in the singlepoint ion collector. If there is a pressure of a neutral gas such as argon or helium in the gas cell, then ion-molecule collisions occur, with decomposition of some of the selected incident ions. This is the MS/MS mode. However, without the orthogonal TOF section, since there is no further separation by m/z value, the new ions produced in the gas cell would not be separated into individual m/z values before they reached the detector. Before the MS/MS mode can be used, the instrument must be operated in its hybrid state, as discussed below. [Pg.159]

The hybrid can be used with El, Cl, FI, FD, LSIMS, APCI, ES, and MALDI ionization/inlet systems. The nature of the hybrid leads to high sensitivity in both MS and MS/MS modes, and there is rapid switching between the two. The combination is particularly useful for biochemical and environmental analyses because of its high sensitivity and the ease of obtaining MS/MS structural information from very small amounts of material. The structural information can be controlled by operating the gas cell at high or low collision energies. [Pg.161]

Collision of an ion with an inert gas molecule leads to some deflection in the ion trajectory. After several collisions, the ion could have been deflected so much that it no longer reaches the detector. This effect attenuates the ion beam as it passes through the gas cell, leading to loss of instrumental sensitivity. An attenuation of 50 to 70% is acceptable and is not unusual in practice. [Pg.228]

Note The initial kinetic energy of slow ions can be lost upon several collisions, thereby stopping their motion along the cell. [119,120] Under such conditions, the continuous ion current into the cell is the only impetus to push the ions through as a result of space-charge effects. The resulting dwell time of about 10 ms allows up to about 5000 (reactive) collisions to take place at some 5 Pa collision gas (or reagent gas) pressure in an octopole collision cell. [123]... [Pg.152]

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. [Pg.154]

Examples of these scan modes will be described below, however a fundamental description of each will be provided in this section. All three MS/MS scans require Q1 and Q3 resolving and a collision gas (usually Argon) must be present in Q2 at a typical target thickness of ca. 10 cm"2 or 10" torr pressure. The nominal ion energy through the Q2 collision cell is ca. 70eV. [Pg.79]

The figures of merit of quadrupole-based ICP-MS, such as the precision of isotope ratio measurements and the detection limits, can be improved significantly, especially for elements which are difficult to determine due to the appearance of isobaric interferences (e.g., by the trace, ultratrace and/or isotope ratio measurements of Ca, Fe, S, As, I or Se).16-22 The occurrence of interference problem can be minimized by the insertion of a collision/reaction cell in ICP-MS as the result of defined collision induced reactions using selected collision/reaction gases or gas mixtures (such as H2, He, NH3, 02, CH4 and others). For each analytical problem, which is different, e.g., for U or... [Pg.123]


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