N2 and O2 peak seperation - TCD gas chromatography

[mehmetsenbayram6]

Hi everybody.
I have a Varian GC. I am recently measuring N2 and O2 with TCD. Carier gas is He. However I have a following problem; when the O2 concentraion is too high (21 %) and N2 concentration is too low 5ppm, N2 gas is overlapping with O2 gas (very very tiny N2 peak). Does anybody have any idea how to improve the seperation of these gases
Thanks in advance

[chromatographer1]

Lower the oven temprtature.

Increase the activation of the molecular sieve packing.

Lengthen the MS column.

Decrease the sample size of the gas injection or increase the diameter of the column.

best wishes,

Rod