Chromatography Forum

Dear all,
All the items of the auto tune of our GC-MS DSQ II are passed, but we noticed that the peaks of 420 and 502 are split peaks and too noisy.
Have you any idea about the cause of this problem and its solution?

Please note that:
1- The background scan spectrum from 10 to 650 is ok.
2- The air/water spectrum from 10 to 90 is ok.
4- All the diagnostics are ok.
5- The DC/RF value is 0.963
6- The detector gain value is 3e5

Thank you in advance

What's your source temp?

The source temp. is 200 C

We work at 250°c but to me it seems unlikely to be the cause of your problem.
Have you changed the ion volume?
If so, is your source and pre-filter clean?

how is your background when scanning from 50-650? (by starting at 50 you eleminate the larger peaks of air and water and get a better vieuw of the noise).

BMu

thanks
the ion volume and lenses and the prefilter were cleaned.
The background from 50 to 650 is a little bit noisy.
Please advise

Thanks

mmhh, 50-650 will always have more noise because you eliminate the high peaks of water and N2. But if you see just noise and no obvious peaks or patern it should be ok. The system has been cleaned so that should be ok.

I guess its about time to call in a service tech. :-s

Thanks