Glossary - Thermo Scientific LTQ Series Hardware Manual

Glossary

A B C D E F
A
API ion transfer tube A tube assembly that assists in
desolvating ions that are produced by the ESI, NSI,
or APCI probe.
API ion transfer tube offset voltage A dc voltage
applied to the ion transfer tube. The voltage is
positive for positive ions and negative for negative
ions.
API source The sample interface between the LC and
the mass spectrometer. It consists of the API probe
(ESI or APCI) and API stack.
API stack Consists of the components of the API
source that are held under vacuum and includes the
API spray shield, API ion transfer tube, API tube
lens, skimmer, the ion transfer tube mount, and the
tube lens and skimmer mount.
API tube lens A lens in the API source that separates
ions from neutral particles as they leave the ion
transfer tube. A potential applied to the tube lens
focuses the ions toward the opening of the skimmer
and helps to dissociate adduct ions.
API tube lens offset voltage A DC voltage applied to
the tube lens. The value is normally tuned for a
specific compound.
API tube-skimmer region The area between the tube
and the skimmer, which is surrounded by the tube
lens. It is also the area of first-stage evacuation in the
API source.
Thermo Scientific
G H I J K L M N O P Q R S T
atmospheric pressure chemical ionization (APCI) A
soft ionization technique done in an ion source
operating at atmospheric pressure. Electrons from a
corona discharge initiate the process by ionizing the
mobile phase vapor molecules. A reagent gas forms,
which efficiently produces positive and negative ions
of the analyte through a complex series of chemical
reactions.
atmospheric pressure ionization (API) Ionization
performed at atmospheric pressure by using
atmospheric pressure chemical ionization (APCI),
electrospray ionization (ESI), or nanospray
ionization (NSI).
atmospheric pressure photoionization (APPI) A
soft ionization technique that shows an ion generated
from a molecule when it interacts with a photon
from a light source.
Automatic Gain Control™ (AGC) Sets the ion
injection time to maintain the optimum quantity of
ions for each scan. With AGC on, the scan function
consists of a prescan and an analytical scan.
autosampler The device used to inject samples
automatically into the inlet of a chromatograph.
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