pls help! The LC-MS suddenly stop running with errow remind

[wendyguo]

Hi all,
I am quite new to LC-MS. Previously another person in the lab was the main user of the instrument, so I just put my samples in and did not need to worry.
But now he left and the many problems coming out.
The biggest problem is the suddenly stop running problem. It would tell me there were errors. Then I checked the logbook. The error was always "the instrument is sending more spectra than the software can accept".
If I shutdown the software and restart it, sometimes it would go on running. But after several samples, the same error coming out again.
At the same time, I found the retention time was increasing in different runs; the baseline was rising and noisy.
I thought it might be some residue in the ion source. So I wiped the spray chamber with 50% MeOH and sonicate the spray shield in 50% MeOH.
The baseline looked better after each clean.
But the problem was still there.
Can anyone give me some advice?
Looking forward to your kindly reply!
Please, excuse my poor English.

[Alp]

I wonder if it is the cleaning of the "spray shield", the wipe down of the source "spray chamber" or just the fact that the equipment may have been stopped for a period and opened up to the room atmosphere.

What type of mass spectrometer are you using?

Is your "spray chamber" being properly vented to refresh the atmosphere inside the spray chamber?

I have not seen your sprayer, but I'll take an educated guess...Is it possible to adjust your sprayer so that the inner tube that carries the column eluant sticks out just a bit longer than the outer tube that carries the nebulizing gas flow?

Alp

[lmh]

I don't know your particular instrument, but taking the error at face-value (always dangerous! Who knows what was going through the programmer's head when he/she wrote the error), it looks like your PC isn't accepting data as fast as the instrument is generating it.
Check that your method is still the one that used to work (hasn't got more scan events or longer, more detailed spectra). Check the PC isn't doing 48 other things on the side (other applications running, virus check busy checking and taking 50% of disk access time...)

[wendyguo]

I wonder if it is the cleaning of the "spray shield", the wipe down of the source "spray chamber" or just the fact that the equipment may have been stopped for a period and opened up to the room atmosphere.

What type of mass spectrometer are you using?

Is your "spray chamber" being properly vented to refresh the atmosphere inside the spray chamber?

I have not seen your sprayer, but I'll take an educated guess...Is it possible to adjust your sprayer so that the inner tube that carries the column eluant sticks out just a bit longer than the outer tube that carries the nebulizing gas flow?

Alp

Thank you so much!!
Well, I always shutdown the MS first and then clean it. Furthermore, the suddenly stopping problem happened before I clean the spray chamber.
The MS that I am using is Agilent G6220.
I cannot quite understand what you meant (fresh to LC..., you know). I don't know how to vent and don't dare to adjust the sprayer . Will this destroy something if I am not careful enough?

[wendyguo]

I don't know your particular instrument, but taking the error at face-value (always dangerous! Who knows what was going through the programmer's head when he/she wrote the error), it looks like your PC isn't accepting data as fast as the instrument is generating it.
Check that your method is still the one that used to work (hasn't got more scan events or longer, more detailed spectra). Check the PC isn't doing 48 other things on the side (other applications running, virus check busy checking and taking 50% of disk access time...)

Thank you!!
The problem is I did not record the detail from the previous method and then cannot be sure whether the current one is the same to the previous one. But I haven't changed anything before and after the problem happened.
Sometimes I will do the qualitative analysis at the same time for quick checking the result. Maybe I should not do it anymore.
I found the data acquisition rate for the TOF Spectra is 3 spectra/s. I don't know if this is too high for the software. I now changed it to 1 spectra/s and run some blanks to see whether it will help.

[Alp]

Sorry, I am not familiar with the Agilent G6220.

All the systems I have used (Sciex) vent the source to waste continuously. Some electrosprayers have the eluant tube within the nebulizer gas tube. I find it best to have the inner tube extend just past the outer tube on these sorts of nebulizers i have used.
Other nebulaizers have different geometries that might negate this possibility of matrix/eluant contaminating the nebulizer itself.