Reservoir inlet system

Highly volatile samples cannot be introduced into the ion source by means of a direct insertion probe even when cooling is applied. A reference inlet system or reservoir inlet system is better suited for that purpose. [59] The name of this type of... 

Section 6.4 deals with other EI-MS analyses of samples, i.e. analyses using direct introduction methods (reservoir or reference inlet system and direct insertion probe). Applications of hyphenated electron impact mass-spectrometric techniques for poly-mer/additive analysis are described elsewhere GC-MS (Section 7.3.1.2), LC-PB-MS (Section 7.3.3.2), SFC-MS (Section 13.2.2) and TLC-MS (Section 7.3.5.4). 

Note Sample introduction systems such as reservoir inlets, chromatographs, and various types of direct probes (Chap. 5.3) are of equal importance to other ionization methods. The same holds valid for the concepts of sensitivity, detection limit, and signal-to-noise ratio (Chap. 5.2.4) and finally to all sorts of ion chromatograms (Chap. 5.4). 

For the purpose of sample introduction, any sample introduction system (also sample inlet system or inlet) suitable for the respective compound can be employed. Hence, direct probes, reservoir inlets, gas chromatographs and even liquid chromatographs can be attached to an El ion source. Which of these inlet systems is to be preferred depends on the type of sample going to be analyzed. Whatever type the inlet system may be, it has to manage the same basic task, i.e., the transfer of the analyte from atmospheric conditions into the high vacuum of the El ion source Table 5.1 provides an overview. 

The liquid introduction system represents another variation of reservoir inlets. Here, the ion source housing serves as the reservoir into which a few microliters of liquid are introduced by means of a kind of micro DIP . [62]... 

Batch inlet systems are in many ways the most convenient for gases and volatile, thermally stable liquids or solids, provided there is sufficient sample available. They consist of reservoirs, varying in volume from 20 ml to several liters, which are connected to the ion source via a molecular leak, usually a porous ceramic material, or a pinhole in thin gold foil or glass. The leak serves to reduce the pressure from 10 torr in the inlet system to torr in the ion source. Large ballast bulbs... 

Vaporize compounds of varying volatility. This is accomplished in the inlet system. Introduction of the sample is done by direct insertion probe, reservoir inlet, or following a chromatographic separation (GC, HPLC, and CE). As mentioned earlier, to introduce the LC flow to the mass spectrometer on-line, we need an appropriate interface. Development of appropriate interfaces was the utmost for evolution of the LC-MS coupling. 

In this system, solvent from a pressure-equalized reservoir (500 ml capacity) is introduced, under controlled flow, into a concentration chamber (Figure 10.3) [3], Glass indentations regulate the boiling of solvent so that bumping does not occur. This reservoir is surrounded by a heater. The solvent reservoir inlet is situated under the level of the heater, just above the final concentration chamber. This chamber is calibrated to 1.0 and 0.5 ml volumes. A distillation column is connected to the concentration chamber. Located near the top of the column are four rows of glass indentations which serve to increase the surface area. Attached to the top of the column is a solvent-recovery condenser with an outlet to collect, and hence recover the solvent. 

Dimethylberyllium forms both 1 1 and 1 2 complexes with tertiary amines. The 1 1 complex with trimethylamine is reported to be stable in the gas phase, but an attempt to determine the molecular structure by gas-phase electron diffraction was unseccessful. The scattering pattern recorded at a reservoir temperature of 65 °C and a nozzle temperature of 85 °C showed that the gas jet must have consisted of nearly 100% trimethylamine l Clearly, the complex had dissociated and the dimethylberyllium had condensed on the walls of the inlet system. 

Mass spectra can be recorded by using any one of several different systems of instrumentation. The inlet system can be either a hot reservoir inlet, a direct-probe inlet, or a gas-liquid chromatography (g.l.c.) inlet. The type of instrumentation and, especially, the inlet system may cause differences in the spectra recorded. However, with modern commercial instruments, these differences are generally small. Combined gas-liquid chromatography-mass spectrometry (g.l.c.-m.s.) has become increasingly important, and is particularly valuable for investigating complex mixtures. Gas-liquid chromatography of carbohydrates and their derivatives is the subject of articles in this Series. "... 

There are different types of instruments that can be attached to the El source for MS analysis. The most commonly used technique consists of the analysis of a gaseous sample obtained from the gas chromatograph. However, other introduction systems, such as reservoir inlets and direct insertion probes, are also frequently used. 

Note The below-mentioned sample introduction systems (reservoir inlets, various direct insertion probes, and chromatographs) are of equal importance to other ionization methods. 

The above example is a simple one, and it can be seen that the individual items form part of the chain in the production system, in which the items are dependent on each other. For example, the operating pressure and temperature of the separators will determine the inlet conditions for the export pump. System modelling may be performed to determine the impact of a change of conditions in one part of the process to the overall system performance. This involves linking together the mathematical simulation of the components, e.g. the reservoir simulation, tubing performance, process simulation, and pipeline behaviour programmes. In this way the dependencies can be modelled, and sensitivities can be performed as calculations prior to implementation. 

Fig. 4. Diagram of a hoUow-fiber ultrafilter filtration system where A corresponds to the retentate reservoir B, circulation pump C, pressure gauge at module inlet D, ultrafilter module E, permeate reservoir F, pressure gauge at module outlet G, value to control module outlet pressure and H, drain...

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