Chromatography Forum

Hi, all -

I'm a GC novice. We have a method that requires us to use our TCD instead of the FID. We get no peaks at all. There is a "make up" line that has a gauge indicating this make-up gas should go to the TCD. HOWEVER - it appears that the line is plumbed into the FID.

Does this make sense?

We'd like to use both detectors.

H_H

Someone used the TCD makeup line to add makeup or to supply air to the FID. Don't use or turn on the TCD without makeup gas, you may burn out the TCD and have to buy another one.

Rod

I'm a GC novice. We have a method that requires us to use our TCD instead of the FID. We get no peaks at all. There is a "make up" line that has a gauge indicating this make-up gas should go to the TCD. HOWEVER - it appears that the line is plumbed into the FID.

Is this a GC-17A and are the make-up gas and the hydrogen gas connecting with a t-fitting that then goes to the FID?

As Rod said, using the TCD without make-up will seriously damage it. Indeed, you may already have done so.

No sample details ? FID is several orders of magnitude more sensitive than TCD what are you looking for at what level ?