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short column life

Discussions about GC and other "gas phase" separation techniques.

3 posts Page 1 of 1
Hi all,

I have a Agilent 6890/5973 GC/MS that is approximately 12 years old. We have been doing the same analysis on it the entire time it has been in our laboratory-a screen for about 50 pesticides. Typical column life for this instrument with this analysis and our sample load is about 6-8 months. In the last year, we have noticed that the column life is decreasing, sometimes needing to change in less than 2 months. Sample prep has not changed, maintenance is being done routinely, and I am stumped at what is causing the short life. Inlet maintenance (septa, liner, gold seal, column cut-back) has been done continuously, we have changed the split vent lines and cartridge, we have cleaned the inlet with a gun barrel brush. We have changed the syringe. I would appreciate any suggestions you might have to try, it is frustrating to have to change the column this often. Thanks!
Hello

I'd use guard column (no stationary phase) - 1-1.5m. It is recommended for COC inlet but it is good idea for other inlets as well.
You can also try to cut 0.5-1m column from inlet side and bake out column overnight (perhaps higher temperature for postrun method would help)

Regards

Tomasz Kubowicz
The one thing that you do not mention is the quality of your carrier gas - do you have oxygen and moisture scrubbers, and are they still working ?

Peter
Peter Apps
3 posts Page 1 of 1

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