Most of them are interfaced to liquid chromatography separations, though they are increasingly used also with gas chromatography and ambient ionization methods.
The ionization method of creating cathode rays used in Crookes tubes is today only used in a few specialized gas discharge tubes such as krytrons.
The ionization method was to strip the outer electron from the propellant upon contact with a tungsten electrode that had voltage applied.
Other ionization methods had been used in the past with similar results.
Electrospray ionization allows a wider range of substances to be analysed than other ionization methods, due to its ability to ionize samples without thermal degradation.
There are several ionization methods: electron impact, chemical ionization, electrospray, fast atom bombardment, matrix assisted laser desorption ionization, and others.
Typically only one ionization method being used at any given time.
Atmospheric-pressure chemical ionization (APCI) is an ionization method used in mass spectrometry.
An ionization method for the absolute measurement of -ray energy.
It is a selective and sensitive ionization method for aromatic and polyaromatic compounds.