Chromatography Forum

I have been collecting data for the last few months and was getting close to wrapping up my first project until we had a power outage last week. The power went out for around 20 minutes to the GCMS, and since then the instrument has not been operational. Below is an example of the same sample ran before the outage (black) and after the outage (red, blue, pink).

https://drive.google.com/file/d/0B6JoSk ... sp=sharing

As can be seen, the baseline is higher, the sensitivity is way lower, and there is no symmetry. This leads me to believe that there was an issue with the mass spec so I did a full tune today. I will attach the tune report. When I look at this report nothing stands out to place the instrument in such an unfunctional state. Can you please advise anything you think I can do to it? Does the tune report indicate any damages by the power outage?

https://drive.google.com/file/d/0B6JoSk ... sp=sharing

Sure you don't have a leak? The N2 and O2 combined are greater than 20%, in my world this spells a leak.

Sure you don't have a leak? The N2 and O2 combined are greater than 20%, in my world this spells a leak.

I'm wondering that also, if all vacuum was lost during the 20 minutes the side door could have loosened enough that it leaks when the vacuum was turned back on.

Sure you don't have a leak? The N2 and O2 combined are greater than 20%, in my world this spells a leak.

I'm wondering that also, if all vacuum was lost during the 20 minutes the side door could have loosened enough that it leaks when the vacuum was turned back on.

The values look relatively normal compared to what I usually get. The only thing that is off is the sensitivity of the standards but only by a little. The 69 m/z peak is typically around 35 million. However, this does not seem to be enough to lower the sensitivity by that much!

The GCMS was running when it shut off. Do you think that could clog the column or inlet or something like that with the sample? I tried to bake it but see no improvement.

Does anything else in the tune besides the possibility of a leak standout?

Sure you don't have a leak? The N2 and O2 combined are greater than 20%, in my world this spells a leak.

I'm wondering that also, if all vacuum was lost during the 20 minutes the side door could have loosened enough that it leaks when the vacuum was turned back on.

The values look relatively normal compared to what I usually get. The only thing that is off is the sensitivity of the standards but only by a little. The 69 m/z peak is typically around 35 million. However, this does not seem to be enough to lower the sensitivity by that much!

The GCMS was running when it shut off. Do you think that could clog the column or inlet or something like that with the sample? I tried to bake it but see no improvement.

Does anything else in the tune besides the possibility of a leak standout?

If the tune is ok but chromatographic peaks are tailing then that would be inlet or column related most likely, unless you have gross contamination of the source somehow, but then that should affect the tune ratios too.

I will try to look at the links when I get home tonight, can't view them at work since they are blocked.