GCMS vacuum pressure

[mrrogers]

I changed out the rotary pump on a Shimadzu QP2010, and the vacuum pressure will only go down to 5.2 when before the change it would go down to 2.3. I've tried changing the liner, o-ring, nuts/ferrels, checked for leaks, and nothing seems to help lower the pressure back to what it was before the switch. Other things that have been tried are switching to a second backup pump, clipping off a part of the tubing connecting the pump. The GCMS still works with this higher pressure, but I've lost about two fold sensitivity because of it.

[Fat Jonny]

Did you just manually check for leaks or did you check by MS? Any mass 18, 28, 32 signals during tuning?

Can you go back to the old pump? If you still can't get down to the low vacuum with the old pump, then I'd suggest you have a leak. If you can, get down to the low vacuum then it would be a pump issue.

[mrrogers]

Thanks for the reply. I actually got the pressure to drop, following a second pressure test, and re-alligning of the ion box.

[pueblito]

Dear mrrogers.
Im working in a Shimadzu QP2010 too.
I would like to know if you perform EPA 8270 test method, especially for organochlorine pesticides.
many thanks.

[mrrogers]

I use the 2010 to quantify known brain/plasma sterols using deuterated internal standards and SIM. Sorry, but I've never worked with the method you are asking about.

[pueblito]

thanks for your reply mrrogers.
by the way, when you clean the ion source box, do you polish the ion source trough all its surface or only some parts of it?, because the manual does not indicate it clearly. and, after that what is the voltage of your detector?
thank you.

[mrrogers]

I polish any part that looks dirty, it is pretty easy to tell once you take it out. I use a cotton swab though and not sand paper as I think the manual suggests. The voltage doesn't really change when I clean the ion box (I'm assuming you are talking about the auto tunning voltage), which for me is usually around .83

[indianolajohn]

I polish the ion source, the repeller, and the entire lens stack
and sometimes the prerods just depending on how i feel that day

[Grace2007]

Thanks for the reply. I actually got the pressure to drop, following a second pressure test, and re-alligning of the ion box.

Hello mrrogers,

what is your pressure right now? I suppose it should be less than 1? anyone knows the criteria of this vacuum pressure?

Grace

[mrrogers]

I guessing you ment to ask what the voltage was and not the pressure (as the pressure gets set depending on the method file). My voltage is between .8 and .9. That will vary depending on the pressure I have it set at when I run the autotune. From what I've learned you want the voltage for you method to be slightly higher than what it is running when you autotune.

[Grace2007]

[quote="mrrogers"]

Hi Mrrogers,

Thanks for your reply!

I mean the vacuum pressure, our GCMS's vacuum pressure is always less than 1pa no matter what method I use. You said your is ~2 or 5, I want to know what it is right now.

When our GCMS is dirty, the valtage can be 1.2. but I think as long as it is <1.5, it is OK.

Grace

[mrrogers]

The vacuum pressure on our machine is typically less than one, but I have a method (from someone's published paper that works really well for quantification of my analytes of interest) that uses an inlet pressure of 89.9 kpa, which jumps the vacuum pressure up between 3 to 4e^000, although I get very clean chromatograms so there doesn't seem to be an issue.

[CRISTINA DURAN]

Dear Pueblito:

I'm working with a GCMS-QP2010 too, we had have a lot of problems with this equipment: the TMP1 brokendown and we replaced it, now the MS doesn't work correctly (dirtness) and we had have a lot of others problems. We would contact with other SHIMADZU users for comment it.

THanks

Dear mrrogers.
Im working in a Shimadzu QP2010 too.
I would like to know if you perform EPA 8270 test method, especially for organochlorine pesticides.
many thanks.

[GC2010]

All instruments can and will have problems. Many related on the care and use of the instrument. Pumps have a service life. What does this have to do with the topic.

Dear Pueblito:

I'm working with a GCMS-QP2010 too, we had have a lot of problems with this equipment: the TMP1 brokendown and we replaced it, now the MS doesn't work correctly (dirtness) and we had have a lot of others problems. We would contact with other SHIMADZU users for comment it.

THanks

Dear mrrogers.
Im working in a Shimadzu QP2010 too.
I would like to know if you perform EPA 8270 test method, especially for organochlorine pesticides.
many thanks.