Varian TCD heating up rate

[Jonathanz]

Does anybody know the Varian 450 GC TCD detector heating up rate? It took 45 minutes to heat up the detector from 50 degree C to 220 degree C. That's way too long! Is this the usual case? Thanks a lot.

[oncoming storm]

I have a Varian 3800 GC and when I turn on the TCD it usually takes about an hour to heat up to 200 and equillibrate. I think it's a normal thing for the Varian instruments but you could always ask your sales rep.

[Spuzzin]

I agree with oncoming storm on this point. The TCDs on the varian instruments take about an hour to heat up and stabilise. Can I ask why 45 minutes is too long ?

Rich

[AICMM]

Thermal stability is one of the key factors in noise in a TCD. That is why Varian puts a big block o' metal around their TCD to establish that thermal equilibrium. Agilent uses the flow switching scheme to try to alleviate this situation but my limited experience with Agilent TCD I still had to wait a while before real stability was obtained.

Best regards.

[jmartin]

My experience has been the same. Just keep the detector hot, even overnight when its not in use. Its better for the life of the detector, as long as there is pure carrier gas flowing through it. I recommend turning the filaments off to extend their lifetime, besides, they have no trouble heating up.

JM