Chromatography Forum

Hello,

Is there anybody really well versed in Tuning of the MSD5973?

I reinstalled this instrument together with a GC6890 after moving of our lab and now got some trouble with the MS parameters.

First something was completely wrong and I got spectra where the masses were shifted by 2 to 4 mass units. Probably I had a wrong tune file, the masses are all right again. But still the relative abundances listet in the tune report and also the abundances of the isotope masses are different from those in old tune reports collected over years (the instrument was bought in 2001).

The tuning substance is PFTBA with the characteristic masses 69, 219 and 502. The relative abundances are 100 for mass 69 (per definition), about 90 for mass 219 (earlier <50) and about 12 for mass 502 (earlier <5).
The isotope 503 of mass 502 is badly resolved compared to earlier reports.

What can I do to solve this problem and is it really a problem? The chromatography is working, but I'm not sure if might still be a shift in the masses.

Thanks for any help
Emsman

I'm assuming that you reset the tune parameters to "default" and tried that first?

Hi
have you changed chemstation sw also? in newest revision tuning algoritm is slightly different and tends to parameter similar to those you have reported.
Anyway... I think that your tune is not so bad with these values...
Good luck

You have write:
I reinstalled this instrument together with a GC6890 after moving of our lab

Verify the dipping of your quad

Hi!

Is the shape of the ion peaks bad?

Did you try with a "Set RFPA"?

I think that the RFPA is dis-"set" (desajustado).

Sorry for my bad English.

Hey Emsman,

I had a similar problem. Check your dc polarity.

I had a simular problem once when we moved our 5973.
But your tune values look normal to me. I would check your DC polarity like someone else suggested. Factory polarity should be marked on the rear of the analyzer. Otherwise I'd just run with it.

Mike