Dear friends,

I have conducted biogas analysis.(Consisting methane and Co2).Please see attached analyses. I am getting extra first peak which i could not able to identify it. Can you guess what is it and how to solve this.
GC Conditions are

Inlet temp: 40 C
Oven: 40 C
Detector: 100 C
Inlet flow : 25 ml/min
Carrie gas: Hydrogen
TCD Sensitivit- 10
Instrument: YL 6500 GC
Column : Porapck Q(4mtrs x 1/8" SS column P/w Porapak-Q)

Please suggest me