Hi,

I am trying to detect N2O using an Agilent 7890a GC-uECD using Markes Application note 018 for info.

I am using a GS-Gas Pro capillary column, oven temp 150C for 10mins, inlet 100C, uECD temp 260C, N2 carrier.

I have run 2 standards: 1 - 10ppm N2O, 100ppm CH4, in N2 / 2- 50ppm N2O, 500ppm CH4, in N2.

and tested ambient air as a check.

I am seeing the same peak around 2.5mins into the run at the same level in both the two standard gases and ambient air. I am not seeing any other peaks.

Please could someone advise me as to why I am not seeing N2O and what the peak at 2.5mins is?

I have attached a picture of the peaks overlaid.

Thank you in advance.