This Information Applies To: Agilent 5975, and 5977 Series GC/MSD
After maintenance requiring venting of the GC/MSD such as a GC capillary column change, filament replacement or abrasive ion source cleaning there will be a decreasing chemical background in the MSD after re-establishing high vacuum. The decrease in chemical background can be accelerated to a stable chemical background by a bake out of the MSD analyzer.
Steps to follow
Caution: GC/MSD bake-out must not be used to attempt to fix or find air leaks. Only bake the MSD, if the system is air leak free, baking the system in the presence of air leaks may cause contamination or damage to the ion source.
Prior to bake out ensure that the ion source has been correctly cleaned, correctly assembled and re-installed in the MSD analyzer and the MSD pumped down.
Refer to the following articles:
Prior to Bake Out, check that the Air and Water Background is acceptable, please review:
If a significant Air Leak is present review:
Troubleshooting Agilent 5975 and 5977 GC/MS Air Leaks and resolve the air leak.
Click Instrument > GC Parameters > Columns - set the Gas Chromatograph column flow to 1.2 ml/min then Apply and Exit back to the main menu
Figure1. Setting column flow
Click View > Tune and Vacuum Control
Figure 2. Tune and Vacuum Control location
Click Execute> Bake out MSD and then set the following parameters
Source bake temperature: 300 °C
Quad bake temperature: 200 °C
Bake Time: 6 hours (typically 1 to 6 hours)
Figure 3. Bake Out parameters
Click Ok to start the Bake Out cycle. When the bake time finishes, it may take at least one hour for the source and quad to return to the temperatures set in the tune file.
Learn how to effectively maintain your Agilent GC/MSD:
GCMS-5977-2260e - Agilent 5977B GC/MSD Diagnostics and Troubleshooting using MassHunter Software
Agilent 5977 GC/MSD with MassHunter Workstation
GCMS-5975-2200r - Agilent 7890/5975 GC/MS Maintenance Overview e-learning courses available from Agilent education