Lockspray Source And Ionization Modes; Electrospray Ionization (Esi) - Waters Xevo G2-XS QTof Overview And Maintenance Manual

1.2 LockSpray source and ionization modes

The LockSpray source uses lock-mass correction to acquire accurate-mass data. The analyte is
introduced into the source through a probe. A reference flow containing a compound of known
mass flows through a separate ESI probe. An oscillating baffle allows the sprays to be analyzed
as two separate data functions. The lock-mass correction calculated from the reference data is
then applied to the analyte data set.
You can use the LockSpray source with the ESI, APCI, and ESCi ionization modes (see
Configuring the LockSpray Source (Page
Atmospheric Solids Analysis Probe Operator's Guide Supplement (715002034).
Figure 1–3: Xevo G2-XS QTof fitted with LockSpray source
Solvent tray
LockSpray source

1.2.1 Electrospray ionization (ESI)

In ESI, a strong electrical charge is applied to 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.
To operate the LockSpray source in ESI mode, you fit the source enclosure with an ESI probe.
March 31, 2021, 715004496 Ver. 04 (previously released as Rev. D)
44)), and with the ASAP ionization mode (see
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