You wrote:
Thanks for your reply.
I have try increasing the backflush time without any success. If there is a leak in the system, wouldnt the CO peak drop as well?
Not necessarily, if the leak was in the sample valve. I am focused on the retention time of the peaks.
The method is using isothermal throughout the run, so there is no change in column temperature.
Just because the instrument says the temperature is the same doesn't mean it is.
Currently I have not run any hydrocarbon or sulfur samples so contaminants should not be a issue.
Could moisture in the carrier gas cause a drop in CO2? Is CO2 more sensitive to moisture than CO?
The CO2 is more difficult for the catalyst to convert than CO. A loss of efficiency of catalyst conversion could be the problem. CO2 can react with amines forming the carbonate.
Other than the causes for drop in CO2, could it be the CO2 have not stabilize in the system causing a spike in CO2 and now it is trying to stabilize?
Yes, it could be a sample homogeneity issue.
Good luck,
Rodney George