Electrospray Ionization (Esi) Source - Agilent Technologies 6475 User Manual

2 Hardware Overview

Electrospray Ionization (ESI) source

Electrospray Ionization (ESI) source
Electrospray relies in part on chemistry to generate analyte ions in solution
before the analyte reaches the mass spectrometer. The LC eluent is sprayed
(nebulized) into a chamber at atmospheric pressure in the presence of a strong
electrostatic field and heated drying gas.
The electrostatic field causes further dissociation of the analyte molecules. The
heated drying gas causes the solvent in the droplets to evaporate. As the droplets
shrink, the charge concentration in the droplets increases. Eventually, the
repulsive force between ions with like charges exceeds the cohesive forces and
ions are ejected (desorbed) into the gas phase. These ions are attracted to and
pass through a capillary sampling orifice into the mass analyzer.
Figure 5. ESI cover, ion source, and spray shield
Agilent 6475 Triple Quad LC/MS System User Guide 24