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- Posts: 1
- Joined: Tue Jan 21, 2020 10:25 am
Hello all,
I am new to GC, so my question may be naive.
I would like to use a GC for quantifying N2 in a mixture of N2, CO2 and Ar. The concentrations of the latter two can vary widely and are unknown.
We performed a calibration using N2 at different concentrations in Ar. Results using this curve are inconsistent, and even an ambient air sample gave an obviously inaccurate value for N2.
A technician suggested that the issue may be that the gas I used during calibration (Ar) differs from the gases in which N2 is found in the measured samples (Ar and CO2).
The issue is the following: the concentrations of CO2 and Ar vary widely, and are unknown. If calibrations have to be made for all possible combinations (N2 in low Ar and high CO2, high Ar and low CO2, Ar only, CO2 only, and everything in between, all this for a wide range of N2 concentrations), the number of calibration gases to buy is prohibitive.
So, I was wondering:
- Is the issue really the other gases used during calibration, or could a calibration of N2 in Ar work for measuring N2 in different gas mixtures?
- If that is the issue, then how is this problem usually handled (for instance, for determining concentrations of a given gas when the other gases present are unknown) without relying on dozens of calibration gases?
Thank you for reading that far. Any help will be much appreciated.
I am new to GC, so my question may be naive.
I would like to use a GC for quantifying N2 in a mixture of N2, CO2 and Ar. The concentrations of the latter two can vary widely and are unknown.
We performed a calibration using N2 at different concentrations in Ar. Results using this curve are inconsistent, and even an ambient air sample gave an obviously inaccurate value for N2.
A technician suggested that the issue may be that the gas I used during calibration (Ar) differs from the gases in which N2 is found in the measured samples (Ar and CO2).
The issue is the following: the concentrations of CO2 and Ar vary widely, and are unknown. If calibrations have to be made for all possible combinations (N2 in low Ar and high CO2, high Ar and low CO2, Ar only, CO2 only, and everything in between, all this for a wide range of N2 concentrations), the number of calibration gases to buy is prohibitive.
So, I was wondering:
- Is the issue really the other gases used during calibration, or could a calibration of N2 in Ar work for measuring N2 in different gas mixtures?
- If that is the issue, then how is this problem usually handled (for instance, for determining concentrations of a given gas when the other gases present are unknown) without relying on dozens of calibration gases?
Thank you for reading that far. Any help will be much appreciated.
