GC-FID

[mandytan]

I have two FID (flame ionization detector) jets with different exit diameters. One of the jet allows my capillary column to go right through it to the other end/tip while the other does not allow the capillary column to go through the end as the "tip" is narrower.
I am not familiar with the FID jet so which jet should be used?

[Peter Apps]

Assuming that this is on a 5890 or 6890 AgilentYou can use either, but the narrower tip has the advantage that you cannot mistakenly thread the column all the way through it when doing routine installations. There were (are) claims that the narrower tips offered better sensitivity, but I never saw any difference.

Peter

[Consumer Products Guy]

Typically with the 5890 or 6890 and capillary columns, one uses the FID jet with the wider opening, and pushes the column all the way up until it touches, then back out 1 - 2 mm and tighten.

[mandytan]

Thanks guys, I am using an Agilent 7890A GC.

[chromatographer1]

When correctly installed the narrow tip can give a better response on the FID, and is the tip suggested for 0.32mm ID or smaller columns.

The wider tip will allow faster column flow rates without 'blowing out' the flame and is suggested for 0.53mm ID or larger ID capillary columns.

Read your manual carefully. It should describe the different tips available and how to effectively use them with your 7890 GC.

best wishes,

Rod