CO, CH4, CO2 on FID, Hayesep Q

[smcg23]

I am analysing mixtures of hydrocarbons/oxides etc. I am using a HP5890 GC with a hayesep Q column and methanator to see CO, CH4 and CO2. After the last peak (CO2), at approx 5 mins, a huge big peak appears which is off scale - any ideas as to what this could be are appreciated.

[larkl]

I'm not that familiar with the methanator, but wouldn't the later peak(s) be whatever hydrocarbons are in the sample?