Flow tube ion source

Figure 1.4 Schematic of a flowing afterglow apparatus. With the apparatus shown reagent Y can be added at any one of the inlet ports positioned along the flow tube. An off-axis ion detector, as shown in the figure, is often used in quadrupole mass spectrometers to minimize noise from radiation and excited neutral molecules generated upstream in the ion source and in the flow tube. Ions are deflected towards the detector by electrodes (not shown).

Figure A3.5.7. Schematic diagram of a selected ion flow drift tube with supersonic expansion ion source.

In essence, a guided-ion beam is a double mass spectrometer. Figure A3.5.9 shows a schematic diagram of a griided-ion beam apparatus [104]. Ions are created and extracted from an ion source. Many types of source have been used and the choice depends upon the application. Combining a flow tube such as that described in this chapter has proven to be versatile and it ensures the ions are thennalized [105]. After extraction, the ions are mass selected. Many types of mass spectrometer can be used a Wien ExB filter is shown. The ions are then injected into an octopole ion trap. The octopole consists of eight parallel rods arranged on a circle. An RF... 

On leaving the chromatographic column, the liquid flow passes along a narrow tube, into the FAB ion source, and then into the target zone of the fast atoms. 

In static runs gas is supplied to the ion source only at a rate sufficient to compensate the outflow through the leak (0.5 cc./sec. for air, equal to conductance of leak). The gas mixtures were prepared in two 2-liter storage flasks of the gas handling system. Flow runs can be made by passing gas through the ion source. Different flow rates were obtained by interposing capillary tubes in series with the flow system. Flow rates with an average linear velocity of up to 10 meters sec.-1 could be obtained. Since the distance from the foil window to the leak is about 3 cm., the contact time for irradiation at this velocity is some 3 msec. 

Principles and Characteristics Thermospray ionisation (TSP) involves introduction of a relatively high flow (0.2-2mLmin ) of solvent into the ion source of a mass spectrometer, and is therefore suitable as an interface for HPLC-MS, using standard bore columns. A vaporiser probe (essentially a resistively heated capillary tube of about 100 xm i.d.) acts as a transfer line for taking solvent and solute into the source. The source is heated to prevent condensation of the solvent, and the temperature of the capillary is chosen so as to ensure vaporisation of the solvent. In this way, a vapour jet is generated, which contains small, electrically charged droplets if the solvent is at least partially aqueous and... 

Note Tlie reactions were studied by Fisher and Adams in a SIFT at 300 K.70 CHjOHJ was produced from CHjOH in a high-pressure ion source by reaction 23 and CHJ/HjO by associating CHj from a low-pressure ion source with H20 in the flow tube. Proton affinities (kcal mol 1) are given below each reactant neutral and that of CHjOHis 181.9 kcal mol 1.2 "30... 

To identify the isomeric form of the product of the collisionally stabilized analog of reaction 44 experimentally, Scott et al.92 studied reactions of C3H30+ (C2Hj/CO) produced in that reaction and compared it with that produced directly from propynal in an electron impact ion source or by proton transfer from HCO+ to propynal in the flow tube (these latter two production methods yielded ions with... 

Figure 1. Fast-flow reaction apparatus. Ions or ion clusters are introduced into the flow tube from various sources and reactions proceed after they encounter the reactants added through a ring injector located at a selected position in the flow tube. The disappearance of the reactant ions and formation of products is monitored with the quadrupole mass spectrometer/electron multiplier shown. Taken with permission from ref. 19.

The ion reaction chamber in the present work was at a relatively high pressure (10 torr), so that conditions were similar to those used with our previous pulsed-electron high-pressure sources.8,9 Reactors operating at lower pressures such as 1 torr or less should also be suitable. Thus, ES could probably be easily adapted for use with flow tubes such as FA and SIFT. 

There are several preparative methods for the production of bare metal clusters including the fast flow reactor (PER), the fast flow tube reactor (FTR), the SIDT (24), the GIB (23), and a supersonic cluster beam source (SCBS) (198). Essentially, all of these methods are similar. The first process is to vaporize the metal sample producing atoms, clusters, and ions. Laser vaporization is generally favored although FAB or FIB may be used. The sample is located in a chamber or a tube and so vaporization generally takes place in a confined environment. An inert gas such as helium may be present in the vaporization source or may be pulsed in after the ionization process. 

There are many more types of cluster ion sources than there are neutral cluster sources, in part because of the wide variety of ion-forming techniques available and in part because cluster ion sources are often hybrids of established neutral cluster sources and ion-forming environments. Some non-hybrid ion sources which can generate cluster ions include ion sputter, flow tube. Penning... 

Figure 6. Diagram of our 1-atm ion mobility spectrometer (IMS) apparatus (a) stainless steel source gas dilution volume, (b) septum inlet, (c) needle valve, (d) Nj source gas supply, (e) source and drift gas exhaust, (f) flow meter, (g) pressure transducer, (h) insulated box, (i) drift tube, (j) ion source, (k) Bradbury-Nielson gate, (I) Faraday plate/MS aperture, (m) drift gas inlet, (n) universal joint, (o) electrostatic lens element, (p) quadrupole mass filter, (q) 6"-diffusion pump, (r) first vacuum envelope, (s) channeltron electron multiplier, (t) second vacuum envelope, (u) 3"-dif-fusion pump, (v) Nj drift gas, (w) leak valve, (x) on/off valves, (y) fused silica capillary, (z) 4-liter stainless steel dilution volume, (aa) Nj gas supply.

Figure 4.2 The micro-Flow Tube Reaetor/Mass Spectrometer instrument. 1 — heated gas inlet/vacuum feedthrough, 2 — hot zone of flow tube, 3 — multiion source block, 4 — ion guide, 5 — quadrupole mass spectrometer, 6 — ion guides, 7 — reaction cell, 8 — quadrupole mass spectrometer, 9 — daly detector... 

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