Chromatography Forum

Hi all

We have a HP5973 MSD system.
We have been having "lots of fun" with it recently but the current issue is

I noticed that the air levels were rising compared to the tuning ions of the PFTBA - I couldn't find any leaks in the GC or MS. I then checked the PFTBA vial and found it empty. I refilled the PFTBA vial and purged the valve as per the manual.
I found however that I can't tune the instrument at all - the 69, 219 and 502 ions are not found at all - strangely though when I run a sample I find the ions as normal - the sensitivity is lowered but the spectra of my samples give a good library match as normal.

When I try to manually tune using values recent from recent good tune files I find that I can detect ions such as 18 and 28 when the PFTBA valve is closed but as soon as I open the valve in the manual tune page, all those ions disappear and I don't see any others at all (no 69, 219, 502)
I did wonder whether the PFTBA I added to the calibration vial was still good as we have had for a few years but there was no expiry date on the container (it was still sealed).

Any ideas - is it likely to be the calibrant valve as I think

I have known two 5973s whose tuning compound solenoid valve would occasionally stick closed. If you activated the valve you still heard a click as the solenoid kicked, but the poppet did not lift. The tune just showed noise. If I recall correctly a sharp tap with a screwdriver handle got it working again.

Peter

Thanks for all your help. The problem is fixed. The main problem was that the calibration vial was not fully inserted through the o-ring in the calibration vial holder part - It seemed as though it wouldn't insert any further and then suddenly it would and everything is now okay.


Thanks again
Kevin.

Hi Kevin

Thanks for the feedback. I'm glad it's sorted.

Peter