Principle Of Ionization - Shimadzu IonFocus Instruction Manual

2 Part Names and Functions

2.1.1 Principle of Ionization

The sample solution is drawn into a capillary tube with a high voltage of about
±1 to ±5 kV applied to it.
The nebulizer gas is delivered from the outside of the capillary tube and the
sample is sprayed with the gas, which generates fine droplets that are
electrostatically charged with the same sign as the applied voltage.
During the course of movement, the solvent evaporates from the charged droplets.
The charged droplets disintegrate when the repulsive force among the charges
exceeds the surface tension of the liquid.
The charged droplets are transformed into very fine droplets through repetition
of vaporization and disintegration, and ultimately it is thought that sample ions
are released in the vapor phase. This state is called ion vaporization.
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