How to tune up for APCI or ESCI mode - WKB7804

OBJECTIVE or GOAL

Tune source for APCI or ESCI mode.

ENVIRONMENT

• APCI Probe
• ESCI Probe

PROCEDURE

1. Refer to the mass spectrometer's operator's guide for how to install the APCI probe/source (for APCI mode) and corona pin.
   By default, the pin is around 3 mm above the cone orifice and in a distance at around 7 mm.
   
2. Increase the probe temperature stepwise up to 600 °C and tune the desolvation gas flow for sensitivity (low flow of 200 L/h might be sufficient).
   Note: Especially when using the Probe heater for the first time, it's important to heat up slowly and stepwise. The probe heater might break otherwise.
3. Switch the divert valve to combined and start infusing the sample with the sample syringe simultaneously with the LC flow (e.g. 0.5 mL/min).
4. Mark the probe position so that it is easy to return to the original position for ESI mode.
5. Using the silver caliper, adjust the probe angle position for best sensitivity. This will probably be close to halfway between the cone and the corona pin.
6. Switch to current control and adjust the corona pin current setting for the best sensitivity (usually 2-5 µA).

ADDITIONAL INFORMATION

Note: When voltage mode is applied, glow discharge and instable voltage is observed at around 1.3 kV Corona Voltage. Avoid voltages that leads to instable an readback due to voltage discharge.