Chromatography Forum

Hello I am quite new to HPLC.

Our MSD had to be shut down due to a bad fitting on the nitrogen line - long story. However, we fixed it and saw no leaks but left the cylinder on and found we were loosing nitrogen. Anyway, we decided to check the MSD and we think we heard nitrogen flowing through the system. We turned it off and the sound was gone. However, the thermo technician is saying that no Nitrogen is supposed to be flowing through when the MSD is not turned on. Anyone else has this problem?

Also what does above vacuum trip mean?

Really looking forward to some answer.

What MS do you have?

Hi Again. Of course we have a Thermo MSD. We did try to avoid getting any other Thermo instruments because of their apparent failure to full function in the region. But maybe Thermo HPLCs are not so problematic as the GC Ultras. The engineer said that they are the best systems out there.

It was the fan or something that was producing the noise that I thought was nitrogen. In my defense the first time I ever saw one of these machines set up and working was late March.

Anyway, it appeared to be some communication problems with the MSD. I rebooted and rebooted, until I decided to take out the cables and put them back in and roboot. It came on as it should. From the installation I saw the engineer doing alot of reboots, so I was not so surprised it had given me this problem, He never did say why all the reboots were necessary. I think he did mention something about software.

Ok, I still do not know what vacuum trip means. The manual did not say.

Maybe I should do an intern at your lab No but serious the organisation is looking into having the staff do an intern somewhere that is ISO certified and does pesticide analysis. Any suggestions?

I mean the exact model

Surveyor MSQ Plus.

Please if you had any suggestions in terms of where our lab can do the intern or attachment, let me know.

I've only got larger Thermo model, so the following my not be relevant: our MS has two vacuum measuring devices, a convectron for checking the low-vacuum from the rough pump, and an ion guage to check the high-vacuum deeper in the instrument. This is probably pretty standard to most manufacturers. Ion guages are destroyed if they're turned on at atmospheric pressure, so if the pressure as measured by the convectron goes above a certain value, the ion guage turns off.

At least some Thermo instruments register this as a vacuum failure.

If you are cleaning the instrument, and squirt solvents directly on the ion transfer tube/source, some solvent will be sucked into the instrument, and this can momentarily raise the pressure around the area of the convectron, so it trips out the ion guage. In our instrument, we have to turn it back on manually in the TunePlus program. I don't know if that is what you mean by a vacuum trip?

Thanks lmh. I saw the manual indicating that the light can still be red it there is vacuum trip. I had not idea what the vacuum trip was. The manual did not say. So maybe what you say is what the manual meant.