Noisy/Drifting TCD signal when changing carrier gases

[electrode]

I have an HP 5890 with a new TCD from GOW-Mac installed. I'd like to be able to detect hydrogen, so it seemed like argon would be the best carrier gas to use. The baseline seems to be very noisy and drifting. I've tried using both brand new UHP argon and UHP helium tanks as carrier gases and both give similar responses, so it doesn't seem to be a contamination issue. I've baked out the column, which had been previously giving a stable baseline on another instrument, and I've tried a thermal bake of the TCD with little success.

Anyone have any suggestions? Thanks!

[AICMM]

Electrode,

You flipped the switch on the board? Helium on the board uses more current that nitrogen/argon switch on the board.

Best regards,

AICMM

[electrode]

AICMM,

Thanks for the reply. Yes, I've flipped the switch, but that doesn't seem to be the problem

[electrode]

I should also note that when the detector is isolated from the column flow, the issue is still present, leading me to think it has something to do with the detector and not the gases themselves.