Prepare GC/MS For Column Maintenance

Question

Hello Everyone, 
 I'm very new and don't have much experience in troubleshooting the GC-MS so I need your help. I'm operating on Agilent 7890B and 5977 MSD. Recently I've noticed very big baseline noise. I have changed the inlet septum and liner, which helped a little bit, but not enough. I suspect that contamination might be already in the column so I would like to trim the column and bake it out. Could you please let me know how should I prepare the GC and MSD for this process? I know that I have to cool the oven and inlet to room temperature, but what about the MSD and gas flow? Should I vent the MSD (the column is connected directly to MSD), and what about the carrier gas (He), should I close the cylinder? 
 If someone would be able to help, I will appreciate this a lot. 
 Thank you.

ISH · Answer

Hi 
 For venting follow below link 
 https://community.agilent.com/technical/gcms/w/gcms-wiki/6928/how-to-vent-shut-down-the-gc-msd---ei---masshunter 
 
 After trimming the column, to start the system, follow below link 
 https://community.agilent.com/technical/gcms/w/gcms-wiki/6929/how-to-pump-down-start-the-gc-msd---ei---masshunter 
 For how to install column 
 https://community.agilent.com/technical/gcms/w/gcms-wiki/7937/how-to-install-a-capillary-column-on-5977-series-gc-msd

paulsalverda · Answer

There is more chance of problems with high flow to a Diffusion pump, as the faliure is called a backstream - diffusion pump fluid vapor throughout the system, an incredibly expensive repair. On diffusion pumped systems it is safest to set the system to VENT and let the diffusion pump get cold, about ten minutes, before cutting the head of the column. 
 Make sure and cut enough off, like 30 to 50 cm.

Prepare GC/MS For Column Maintenance

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