How to install the Xevo ESI probe and optimize its position - WKB258305

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Article number: 258305

OBJECTIVE or GOAL

Install the Xevo ESI probe and optimize its position.

ENVIRONMENT

Xevo instruments

PROCEDURE

Two probe design types are available for the Xevo family: the ESI probe (Figure 1) and the Tool-Free ESI probe (Figure 4)
Video: Installing the ESI Probe (Figure 2) and Tool-Free Probe Assembly
The capillary voltage is present only when the instrument is in Operate and is in position on the source enclosure assembly. The capillary voltage is 0 to 5 kV in Operate. It is a positive voltage in Positive Ion mode and a negative voltage in Negative Ion mode.
Set temperatures and gas flows for your application and allow them to stabilize. See the article "For running the mass spectrometer at high flow rates, what are recommended flow rates versus temperature and gas flow?" - WKB204351
Ensure that the probe is locked into place by tightening the probe locking ring (Figures 2, 3, 6).
The following probe parameters can be adjusted:
1. Probe height position with respect to the desolvation heater (when fitted to an API source enclosure)—use the adjustment ring on the source enclosure assembly.
2. Angle of the probe with respect to the cone—use the Vernier micrometer adjustment knob, left of the probe, on the source enclosure.
3. Capillary length, by turning the knob on the top of the probe.
Set the initial horizontal position of the probe by setting the Vernier micrometer adjustment knob on the top of the source housing (Figure 3)to (5) on the Vernier scale. Set the initial vertical position of the probe by setting the vertical probe adjuster to (7) on the Vernier scale. Set the initial capillary protrusion length to 0.5 mm.
Maximize the peak intensity by turning the Vernier horizontal probe adjuster on the probe's mounting flange.
Adjust the capillary voltage for maximum sensitivity. At higher flow rates, capillary voltage may need to be reduced and probe position may need to be adjusted away from the cone.
Optimize the capillary protrusion using the knurled knob atop the ESI probe (Figures 1, 4).
Optimize the sample cone voltage for maximum intensity.

Tip: To ascertain the probe's position, set the capillary voltage to zero. If the signal intensity fails to drop to less than 10% of that observed with optimum capillary voltage, move the probe away from the sample cone slightly. Return the capillary voltage to its previous setting and observe the signal intensity. Repeat as necessary.

Notice: If you position the probe too close or the capillary voltage is too high (especially in Negative Ion mode) to the sample cone, nonlinear data, sample suppression, damage to the capillary, and the need for frequent source cleaning can result.

Removing the probe: Turn off the solvent flow, place the instrument into Standby on the Tune page, disconnect the LC flow line from the probe, clear the selection for API gas flow, disconnect the probe electrical connection, unscrew the probe locking ring, and remove the probe from the source.