I'm a noob in gas chromatography and I need an advice. I recently started working on an old GC-FID which was running for years with packed columns. I was told to switch to a brand new megabore column with internal diameter = 0.53 mm. The stationary phase is unchanged.
However, when I switched them, the peaks of the compounds I'm measuring were almost absent for working stock solutions, and had an ugly shape. I think that the gas flow rates might be the problem. The rates for the old packed column were 17 psi for nitrogen (carrier), 34 psi for hydrogen and 13 psi for air.
How should I adjust the flow rates when switching from packed column to megabore? Should they be increased or decreased?
I think that the installation was done properly, although I heard two different opinions on how deep the column must be inserted into the FID, one stating that the end of the column should be placed just above the FID coil, while the other saying it should be inserted approx next to the hydrogen inlet, which is before the FID coil.