Template:ASMS sample introduction

Sample introduction system: This is a system used to introduce sample to a mass spectrometer ion source before and/or during analysis. (sample introduction system, introduction system, sample inlet system, inlet system, and inlet are synonymous terms.)

Reservoir inlet: This is an inlet system having an enclosed volume (the reservoir), with provision to evacuate the reservoir, to admit sample to the reservoir, and to allow gas or vapor from the reservoir to flow through a leak to the mass spectrometer ion source. A complete description of a reservoir inlet should include a description of the method by which the sample is introduced into the reservoir (e.g. with gas-metering, septum, fritted-disc, or teflon-cup introduction), an indication as to whether the leak provides viscous or molecular flow, and an indication whether the reservoir is heated.

Batch inlet: This is the historic term for a reservoir inlet. Reservoir inlet is preferred because a direct inlet probe is also a form of batch inlet. Batch gas inlet or batch vapor inlet is, however, a completely descriptive term.

Dual viscous-flow reservoir inlet: This is an inlet having two reservoirs, used alternately, each having a leak that provides viscous flow. This inlet is used for making precise comparisons of isotope ratios in two samples.

Continuous inlet: This is an inlet in which gas or vapor passes continuously into a mass spectrometer ion source, as distinguished from a reservoir inlet or a direct inlet probe.

Non-fractionating continuous inlet: This is a continuous inlet in which gas flows from a gas stream being analyzed to the mass spectrometer ion source without any change in the conditions of flow through the inlet or by the conditions of flow through the ion source.

Direct-inlet probe: This is a rod having a sample holder at one end, which is inserted into the vacuum system of a mass spectrometer through a vacuum lock, placing the sample near to, at the entrance of, or within the ion source, so that the sample can be vaporized after introduction to the vacuum system by heat from the ion source or by heat applied to the probe from an external source. (direct inlet probe, direct-introduction probe or direct-insertion probe are synonymous terms. The use of DIP as an abbreviation for these terms is not recommended.)

Vacuum-lock inlet: This is an inlet in which a sample is placed in a chamber, the chamber is pumped out, and a valve is opened so that the sample can then be introduced to the mass spectrometer ion source. A vacuum-lock inlet commonly uses a direct- inlet probe which passes through one or more sliding seals, but other kinds of vacuum-lock inlets are possible.

Extended direct-inlet probe: This probe provides for insertion of a sample on an exposed surface (such as a flat surface or a wire) into (rather than up to the entrance of) the ion source of a mass spectrometer. (This term is synonymous with direct-exposure probe.)

Crucible direct-inlet probe: With this probe, the sample is held in a cup-shaped device (the crucible) rather than on an exposed surface. A direct-inlet probe is assumed to be a crucible type unless otherwise specified.

GC/MS interface: This is an interface between as gas chromatograph and a mass spectrometer which serves to provide continuous introduction to a mass spectrometer ion source of effluent gas from a gas chromatograph during the period for which the effluent gas is to be analyzed.

Direct GC/MS: This is an interface in which the entire effluent from the gas chromatograph passes to the mass spectrometer ion source during an analysis, without any splitting of this effluent.

Splitter GC/MS interface: This is an interface in which the effluent from the gas chromatograph is divided before admisssion to the mass spectrometer, without enrichment of sample with respect to carrier gas.

Separator GC/MS interface: This is an interface in which the effluent from the gas chromatograph is enriched in the ratio of sample to carrier gas. (Separator, molecular separator, and enricher are synonymous terms.) A separator should generally be defined as an effusion separator, a jet separator, or a membrane separator.

Effusion separator (or effusion enricher).: This is an interface in which carrier gas is preferentially removed from the gas entering the mass spectrometer by effusive flow (e.g. through a porous tube or through a slit).

Jet separator: This is an interface in which carrier gas is preferentially removed by diffusion out of a gas jet flowing from a nozzle. (jet separator, jet-orifice separator, jet enricher and jet-orifice enricher are synonymous terms.)

Membrane separator: With this separator, the gas or vapor passes to the mass spectrometer through a semi-permeable membrane (e.g. a silicone membrane) which selectively transmits organic compounds in preference to carrier gas. (Membrane Separator, Membrane Enricher, Semi-Permeable Membrane Separator, and Semi-Permeable Membrane EnrTcher are synonymous terms.)

Solvent-divert system: This system is used in conjunction with an interface which permits temporary interruption of the flow from a gas chromatograph to a mass spectrometer by opening a valve to a pumping line, so that an effluent present at a high concentration (usually solvent) does not enter the mass spectrometer ion source at a high concentration.

Liquid chromatograph/mass spectrometer (LC/MS) interface: This interface is between a liquid chromatograph and a mass spectrometer which serves to provide continuous introduction to a mass spectrometer ion source of the effluent from a liquid chromatograph during the period for which the effluent is to be analyzed.

Moving belt (ribbon or wire) interface: With this interface, all or a part of the effluent from a liquid chromatograph is continously applied to a belt (ribbon or wire), which passes through two or more orifices, with differential pumping, into the mass spectrometer vacuum system; after which heat is applied, to remove the solvent, and then to evaporate the solute into the ion source.

Direct chemical ionization interface: With this interface, all or a part of a liquid chromatograph effluent passes continuously to the mass spectrometer, in which the solvent is used as a chemical ionization agent for ionization of the solute.

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