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Re: Inlet pressure fluctuations and retention time shifts
Posted: Wed Nov 19, 2014 7:40 pm
by Trishia
@Peter - not that I can see. I can find instructions for a 6850, but my 6850 is a networked Series II with no control panel and I couldn't seem to find anything through the software.
Guess I might have to reach out to Agilent for this one.
Thank you all for your help, I really appreciate.
Re: Inlet pressure fluctuations and retention time shifts
Posted: Wed Nov 19, 2014 9:43 pm
by Peter Apps
Hi Trishia
If Agilent do come up with anything please let us know. Fingers crossed.
Peter
Re: Inlet pressure fluctuations and retention time shifts
Posted: Thu Nov 20, 2014 11:03 am
by BMU_VMW
Might be a silly question, but is there an other GC that uses the same He-source?
a problem with this GC might cause a drop in pressure at your GC.
Re: Inlet pressure fluctuations and retention time shifts
Posted: Thu Nov 20, 2014 8:50 pm
by Trishia
Not a bad thought but no, they are hooked up to individual carrier gas cylinders.
Re: Inlet pressure fluctuations and retention time shifts
Posted: Thu Nov 20, 2014 9:09 pm
by dblux_
Can you get to these guts and "sniff" split vent line with leak detector ?
http://www.wasson-ece.com/engineering/i ... ve_top.jpg
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edit:
Althou you already have reached the last paragraph on page 5, but may be worth to have a look on this procedure again
http://www.chem.agilent.com/Library/Sup ... a16020.pdf
Re: Inlet pressure fluctuations and retention time shifts
Posted: Fri Jan 16, 2015 9:32 pm
by Trishia
Just as a follow-up, Agilent did let me know how to re-calibrate the pressure to 0 but I was still experiencing the issue. Running some pressure decay tests, the rate is above normal but try as we may, we cannot locate any leak with the electronic detector (at any point; septa/inlet liner nuts, column inlet, reducing nut under insulation cup, point where carrier gas comes in and septum purge goes out, caps, along the split vent line and trap, all the other lines and the points where they enter the module - nothing and we've checked several times). Even put a cap right on the inlet at the split line point and still saw a leak - in fact, when we depressurize (take off caps and even disconnect the carrier gas at the back of the instrument), total flow rate still reads at 1.4 mL/min when it should be at 0 mL/min. Not sure if this means there is a leak inside the split module or if there is something wrong with the EPC.
If I do figure it out though, I will post back for future reference.
