2 Replies Latest reply on Oct 11, 2018 2:06 AM by gchaplain

    Shutting Down GC-MS System

    denash50

      Hello Everyone,

       

      I am new to the forum and full disclosure not an expert at GC-MS systems. However, I am a chemistry professor at a small liberal-arts school which kind of makes me a jack of all trades and puts me in charge of our instrumentation (I have the most experience of the faculty here). Anyways, we recently purchased and installed a refurbished Agilent 6890-5973 GC-MS system using He gas as our carrier. Currently, this instrument will only be used for teaching purposes, meaning it will only be used a couple of times of year in our Instrumental Analysis course and not for very sensitive quantitative work. With money always tight, I was wondering if it would be okay to shut the system down while it is not being used to conserve He gas. I know it is preferred to keep the system on and pumped down and gas flowing, but we are working to save as much as money as possible, and since the instrument will sit idle for several months, it seems somewhat wasteful to keep it running.

       

      So first, is it possible to leave the MS system under vacuum without the carrier gas on? I would guess this means turning the temperature down or off on the filament, which is fine. I also know we would set the GC oven temperature to ambient while it is shutdown. So any advice I could receive from the experts here is GREATLY appreciated! We want to teach our students the importance of GC-MS, but also do so in an economic fashion!

       

      Thanks again for any help!

        • Re: Shutting Down GC-MS System
          denash50

          Bumping this to the top. Any help is much appreciated! Thank you.

          • Re: Shutting Down GC-MS System
            gchaplain

            Unfortunately, no you can't keep it under vacuum but you can turn off the helium and vent the system. I would recommend keeping the nuts on the side door of the MS closed though to prevent debris entering the MS chamber.

             

            You can vent either by using the software on the PC (under View - Tune and Vacuum control, then Vacuum - Vent) it should take an hour then you can turn it off.

            Or there is an option to Vent from the front panel so if you go to Maintenance on the front panel and then it will ask if you wish to vent the MS, then press Yes. Should take again about an hour.

            You can then turn the MS and GC off and turn the helium off too.

             

            When starting back up, turn on the helium, hold the MS chamber door to the chamber (without touching the electronic) and turn the MS on (roughing pump will be loud then go quiet). Wait until this happens then you can let go of the chamber door. wait 10 seconds then turn the GC on.

             

            Once at temperature check for leaks and leave overnight to clear any air int eh system. by the following day it should be ready for analysis.