Ambient ionization
Encyclopedia
Ambient ionization is a form of ion
ization in which ions are formed outside the mass spectrometer without sample preparation or separation.
ion source
that operates by exposing the sample to a gas stream (typically helium or nitrogen) that contains long-lived electronically or excited neutral atoms, vibronically excited molecules (or "metastables"). Excited state
s are formed in a glow discharge in a chamber through which the gas flows.
source to create charged droplets that are directed at a solid sample. The charged droplets pick up the sample through interaction with the surface and then form highly charged ions that can be sampled into a mass spectrometer.
light. The hot jet thermally desorbs the sample from a surface and the vaporized sample is ionized by a vacuum ultraviolet light and consequently sampled into a mass spectrometer.
desorption/ionization (ELDI) relies on a laser to the desorption of material into the electrospray plume. With matrix-assisted laser desorption electrospray ionization (MALDESI), a nitrogen laser
is used to desorb material into the electrospray. MALDESI has been used with MALDI matrix materials. Laser ablation electrospray ionization (LAESI) uses an infrared laser for ablation of the sample material. The term laserspray ionization has been used to describe transmission mode laser ablation of matrix/analyte mixtures to produce highly charged electrospray-like molecular ions.
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
ization in which ions are formed outside the mass spectrometer without sample preparation or separation.
Direct analysis in real time
Direct analysis in real time (DART) is an atmospheric pressureAtmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...
ion source
Ion source
An ion source is an electro-magnetic device that is used to create charged particles. These are used primarily to form ions for mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters and ion engines.- Electron ionization :...
that operates by exposing the sample to a gas stream (typically helium or nitrogen) that contains long-lived electronically or excited neutral atoms, vibronically excited molecules (or "metastables"). Excited state
Excited state
Excitation is an elevation in energy level above an arbitrary baseline energy state. In physics there is a specific technical definition for energy level which is often associated with an atom being excited to an excited state....
s are formed in a glow discharge in a chamber through which the gas flows.
Desorption electrospray ionization
Desorption electrospray ionization (DESI) uses an electrosprayElectrospray
The name electrospray is used for a device that employs electricity to disperse a liquid or for the fine aerosol resulted in this process. The method is sometimes improperly called electrohydrodynamic atomization. High voltage is applied to a liquid supplied through an emitter...
source to create charged droplets that are directed at a solid sample. The charged droplets pick up the sample through interaction with the surface and then form highly charged ions that can be sampled into a mass spectrometer.
Desorption atmospheric pressure photoionization
Desorption atmospheric pressure photoionization (DAPPI) enables direct analysis of samples deposited on surfaces by means of a jet of hot solvent vapour and ultravioletUltraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
light. The hot jet thermally desorbs the sample from a surface and the vaporized sample is ionized by a vacuum ultraviolet light and consequently sampled into a mass spectrometer.
Laser assisted
Electrospray-assisted laserLaser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
desorption/ionization (ELDI) relies on a laser to the desorption of material into the electrospray plume. With matrix-assisted laser desorption electrospray ionization (MALDESI), a nitrogen laser
Nitrogen laser
A nitrogen laser is a gas laser operating in the ultraviolet range using molecular nitrogen as its gain medium, pumped by an electrical discharge....
is used to desorb material into the electrospray. MALDESI has been used with MALDI matrix materials. Laser ablation electrospray ionization (LAESI) uses an infrared laser for ablation of the sample material. The term laserspray ionization has been used to describe transmission mode laser ablation of matrix/analyte mixtures to produce highly charged electrospray-like molecular ions.