Chromatography Forum

Hi
I'm working on 1100 Agilent LCMSD (single Quadrupole), and trying to make it work( this is used device).
I've setup connections and software and now it's time for vacuum.
Now, I've a problem:
LCMSD starts, rough pump goes to 2 torr(it's OK), turbo1 starts and goes to 99%( power 78 W, seems OK), turbo2 starts and goes to 99%( power 25 W), but high vacuum does not go under 4 mtorr. It goes really fast to 4mtorr, but then no move to lower torrs.
I've check all connections for leak( opened connections, lubed with vacuum grease, tightened), but no success till now.
could you offer me any procedure or give any hints? how much time is required for 10 -5 torr? will you advise for 24 hours vacuum time?

thanks and regards
Bahram

Hello,

The rough pump pressure looks OK and if both turbo's are spinning (listen to them !) you should have a good vacuum except when leaks are present.
However the 'lower torrs' are not reached at once. When the system was opened some seals might no longer be well seated and that can take a while.
It is normal for Agilent quad systems to slowly reach 10-5, 10-6 in 24hours and from then on gradually better (10-6; 10-7) in the next 48 hours or more.
It the pressure does not reach the desired vacuum after 48h you probably have a leak : that can be at the top lid, behind the skimmer, the ion optics seal, the capillary seal. Turbo pump seals, or simply at the connections of the roughpump, or the in between vacuum connections inside the MS.
Also the wrong capillary can be mounted.
Be carefull with vacuum grease, normally this is not needed. If used, use only a very limited amount of Apiezon L, that does not cause background.

Jan

Dear jan
Thanks for your attention.
I'm new in LCMSD. so, I want to know if my devices are OK, or something is going wrong. I'm experienced with GCMSD, and from there, turbo pumps will bring vacuum to 10 -6 in less than 15 minutes.
I've checked all connections on MSD and lubed them with vacuum grease. changed all Orings, and lubed them with vacuum grease. tested almost all possible leak positions, but, nothing changed yet.
I'm working on Agilent 6210 TOF too, with almost same problem.
when I start MSD, rough pump pumps down really fast ( about 10 seconds to reach below 3 torr)
turbo 1 starts and goes to 100% in almost 2-3 mins( airplane engine sound could be heard), then, turbo 2 starts and goes to 100%( turbo sound is OK for it too). turbo1 power is OK, but turbo2 power is 35% higher than standard.( 26W instead of 18-19).
Rough pump vacuum will be steady in 2-2.2 torr.
High vacuum starts from 5.5 mtorr, then goes down to 4.5 mtorr in 1 minute. after that, I see no change. pumps work, no thing changes and vacuum has no noticeable change. I've left 1100 MSD on overnight( 12 hours), but vacuum has no change.

for 6210 TOF, with much bigger chamber, vacuum goes down fast to 1.5 mtorr, then steady vacuum starts and no change in vacuum.

these instruments has been vented for at least 3 years, and this is first pump down. should I do any other cleaning?

1-Please let me know what should be vacuum degree after 0.5 - 1- 3- 6- 12- 24 hours.
2- when I should expect to see 10 -4, 10 -5 torr?
3-I've used vacuum grease on all orings, could this affect vacuum?
4-how much time is needed to remove dirt effect from chamber?
5- what is lowest vacuum( highest pressure) LCMSD can operate?
6- is it possible for turbo pumps to rotate at full speed, but have problem in vacuum?
7- if I contaminate my chamber with moisture and vacuum grease, what could be my vacuum gauge? could this problem be for this reason?
any help and experience will be appreciated.

yours
bahram

Finally, I've solved my problems.
Vacuum should be at least in 10 -5 range in start. if it's not, there is a leak, or leaks.
I've greased all Oring, and turned my 1100 on. everything went well. after 15 min, vacuum was in 10-6 range.

Indeed, at least after 24 to 48 hours on a quad the vacuum should be stable and less than 10-5T or a leak is present.
For the TOF that is an other matter. There it can take up to 2 weeks for the vacuum to reach stable pressure.
Do an initial tune after 1 week or so after startup as otherwise it will not be absolutely stable yet.
Vacuum on the TOF goes down to 10-5 fast but should further go down slowly. I finally reach 4,4.10-7T on a 6220 TOF.

Jan

Dear jan
Thanks so much for your comments.
you're right. few days ago, I started my 6210 TOF, and it's in the same way. fast pump down to 5*10-5, then slowly to 2*10-6, then really slowly down.
by the way, may I ask you for documents about 6210 or 6220? I do not have user manuals, or troubleshooting or so on.
I'll be really happy if you provide me some documents. I'm new in LC/MSD and no body around to help me.
thanks and regards
bahram

Dear friend, you can download these manuals from Agilent's site, at least concept guide and maintenance manual for 6200 TOF systems.
http://www.chem.agilent.com/search/?N=6 ... 0&Ntt=6200
The same for SQ.

Best regards,

Dear friend, you can download these manuals from Agilent's site, at least concept guide and maintenance manual for 6200 TOF systems.
http://www.chem.agilent.com/search/?N=6 ... 0&Ntt=6200
The same for SQ.

Best regards,

Thanks a lot for you help.
will search more in Agilent site.