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- Posts: 3
- Joined: Thu Sep 25, 2014 6:04 pm
I am having a strange problem and I can use any help I can get... My company uses calibration standards for our various GC's and I realized that the gas standards that we are receiving have inconsistencies in the CO2 peak.
For example:
When I receive a cylinder with 10% CO2 in balance N2, I can calibrate my GC to 10%
If I then use a cylinder with 10% CO2 in balance H2 and CH4, the peak area is larger, and my concentration comes out to be closer to 13%!
At first, we believed it was an issue with the gas cylinders, but I have since tried multiple gas suppliers and find this same trend.
I cannot find any information online that says that H2, CH4, or N2 can impact the CO2 reading, but has anyone else ever experienced this or have any ideas?
For reference, we are seeing this on 3 different GC's all of different types of Agilent Micro GC with both He and Ar carrier gases.
One of the GC's in use is a 490 Micro GC using a PPU column with a TCD detector and He carrier gas. There is excellent separation between peaks.
The plot then thickens when our gas providers show us that they use a GC with TCD, but only using a packed column instead and they don't see the inconsistency.
Thank you for any help!! This is driving me crazy!
-Matt