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- Posts: 25
- Joined: Mon Dec 12, 2016 7:24 am
I'm having two problems that I believe are related to my split inlet... I'm quantifying the concentrations of mixtures of C1-C9 hydrocarbons using a gas sampling valve and an FID. The problems are:
1) The total peak areas are highly irreproducible, especially when I use an oven program that starts at cryogenic temperatures. I think this is likely due to fluctuations in the amount of analyte sent through the column vs vented. This isn't really a big deal since I can just normalize by the total peak areas, except...
2) The concentration of aromatics (benzene, toluene, xylenes) I observe stays relatively stable, whereas everything else (methane, ethane, ethylene, propylene, etc.) fluctuates with the total peak areas. The aromatics are at very low pressures (< 1 kPa) so they cannot be condensing.
Does anyone have any idea why this might be happening or any suggestions for fixing it?
Thank you!