(GCMS) Chemical Ionization(CI, NCI) When signal intensity is extremely weak

Cause 1: Either the cylinder valve of the gas cylinder, the control knob of the pressure regulator, or the outlet valve of the pressure regulator is closed. The solenoid valve of the reagent gas control unit is set to OFF.
Action 1: Check each open/close condition. Open it or set it to ON if there is any closed or OFF valve.

Cause 2: The ion source box is not mounted correctly or the cap of the interface is not inserted completely into the ion source box.
Action 2: Stop the instrument and check the state of the ion source. Be sure to turn OFF the power of the instrument.

 

Cause 3: Large amount of reagent gas is being supplied to the ion source.
Action 3: Adjust the control knob of the pressure regulator so that the vacuum degree is set within the specified range.

  Click here for Reagent Gas Setup Procedure.

  Click here for Excessive Introduction of Reagent Gas.

 

Cause 4: The PTFE tube of the ion source is not connected or poorly attached.
Action 4: Stop the instrument and check how the PTFE tube is attached to the ion source.
  Be sure to turn OFF the power supply.

 

Cause 5 Correct type of ion source box is not mounted. Correct repeller electrode spacer is not mounted.
Action 5: Stop the instrument and check the type of ion source and the type of repeller electrode spacer. Be sure to turn OFF the power of the instrument.

  Click here for CI, NCI Ion Source Replacement and Rinsing Procedure.

Cause 6: The ion source box and the repeller electrode are not electrically insulated.
Action 6: Remove the ion source and confirm the insulation between the repeller electrode and the spacer by tester.
  Be sure to turn OFF the power of the instrument when performing the work.

  Click here for CI, NCI Ion Source Replacement and Rinsing Procedure.

 

If none of the above causes applies, contact a Shimadzu sales or service representative.