Chromatography Forum

Hi people!

I work a system GC6980/MSD5973 (with quad, EI, turbo pump), that was working good. But I changed the capillar column and then I conditioned that. After that I executed the Autotune, but that sopped with the message "can't achieve constant peak widths".

The vacuum is good.
There is PFTBA in vial.
The cal valve is open and I hear "click".
Check of leaks is OK (but the ion 69 abundance is very low).
The flow is 0.9, splitless.
The temperature of source is 230°C.
The temperature of quadrupole is 150.

Please help me.

astroquille,

Try changing the filament in use first. It may have become mis-aligned or it may be dying. The next thing I would do is pull my source and clean it. After those two steps,..... well, we go from there.

Best regards.

Hi

I changed the filaments and the problem persists.
I am going to clean the source.
Can the source has lost its "inertness" after some cleanings (or "inert ability"? I don't know how it is said)?

astroquille,

A lab I work with replaces the repeller lens on a fairly routine basis, about once a year or so. They find that this helps maintain system performance. Are you getting any insight into the actual 69 abundance as the system tries to autotune?

Best regards.

Is the column installed properly? If the column is installed too far into the ion source it can interfere with the electron beam from the filament and cause all sorts of problems. The fact this occured after a column change makes me wonder about the column position in the source.

Thanks Ron!

The hardware manual of the MSD 5973 says that the column must be installed 1-to-2 mm into the ion source. That was near 2 mm, inside this range. In spite of that, I put the column near 1 mm into the ion source and the problems left. It's working!!!

Thank you so much again!!!