WATERS CORPORATION TQ, Operator'S Manual, Page: 24 / 192

1 Waters TQ Detector
24 December 6, 2012, 71500126802IVD Rev. C
Ionization techniques and source probes
Electrospray ionization (ESI)
In electrospray ionization (ESI), a strong electrical charge is given the eluent
as it emerges from a nebulizer. The droplets that compose the resultant
aerosol undergo a reduction in size (solvent evaporation). As solvent continues
to evaporate, the charge density increases until the droplet surfaces eject ions
(ion evaporation). The ions can be singly or multiply charged. The multiply
charged ions are of particular interest because the instrument separates them
according to their mass-to-charge ratios (m/z), permitting the detection of
high-molecular-weight compounds.
The instrument can accommodate eluent flow rates of up to 1 mL/min.