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Problem with Autotune on MSD 5973
Posted: Tue Mar 18, 2008 12:25 pm
by astroguille
Hi people!
I work on a GC/MSD (6890/5973) and I cut 1/2 meter of the capilar column last week. I use PFTBA for the autotune.
After that, I performed an Autotune with unexpected results: the Autotune don't finish, with the peaks of the 69, 219 and 502 very bad.
I noted that the peak numbers of the mass spectrum was very low: between 12 and 20. And also I noted that the abundance of the 69 ion was very low too: aproximatly between 4400 and 5000.
What can the problem be?
Posted: Tue Mar 18, 2008 1:53 pm
by darber42
Did you have the source open for source maintenance? Did you re-insert the column back into the transfer line?
Posted: Tue Mar 18, 2008 3:18 pm
by astroguille
I didn´t touch the ion source, at least two mounths ago.
Posted: Tue Mar 18, 2008 7:21 pm
by darber42
Does it give you some sort of error message when the autotune doesn't finish? Did you try running a DFTPP tune instead of an autotune? What kind of analysis do you perform? Maybe it's time for a source cleaning?
Posted: Wed Mar 19, 2008 11:54 am
by astroguille
I analyze pesticides in fruits, vegetables and water. I cleaned the ion source 2 mounths ago.
Posted: Wed Mar 19, 2008 6:56 pm
by danicrd
have you try to use second filament instead of first? Can be a emission problem...
Another way is try ramping all lenses. If you see strange line instead of curve you have a short circuit and need to clean/replace source.
Good luck
Posted: Tue Mar 25, 2008 12:03 pm
by astroguille
I used the second filament and the system doesn't change.
Ionfocus is high: 90.2. In the tune evaluation report, the precursors are high too.
I don't what to do!
Posted: Tue Mar 25, 2008 1:23 pm
by danicrd
The voltage of ionfocus is correct...
Try to check pftba valve: can you hear a click when atune is running? Is there sufficient calgas in the bulb?
If you don't have calgas flow in the source you can't get signal...
How many volts your em is?
And finally..clean the source. Two months can be sufficient to have dirty source.
Good luck.
Posted: Thu Mar 27, 2008 3:36 pm
by Rick
Verifiy is your PFTBA vial is not empty
Posted: Thu Mar 27, 2008 5:20 pm
by astroguille
Yes, I have enough PFTBA
Posted: Thu Mar 27, 2008 5:57 pm
by Rick
Okay for PFTBA.
Check this item now....
Can you heard the ''clic'' of PFTBA valve when she is open?
Have you a big air leak?
Your filament is o.k.?
What is the EM voltage?
What is the flow of your capillary column?
Posted: Thu Mar 27, 2008 6:34 pm
by astroguille
I heard the ''clic'' of PFTBA valve when that is open.
The system doesn't have air leak.
Both filaments are o.k.
EM voltage is aproximatly 1600
The flow of the capillary column is 0.9
Posted: Fri Mar 28, 2008 1:52 pm
by Rick
Can you place your autotune on this site?
Posted: Fri Mar 28, 2008 5:40 pm
by Rick
Hi again...
I'm suspected that your PFTBA don't enter in your MSD.....
Try this..purge your calibration valve
View
Diagnostics
Vacuum
Purge cal valve
Posted: Fri Mar 28, 2008 5:52 pm
by Rick
It's me again....
Verify that your emission current is at 34.6 and electron energy at 69.9