5973N tune issues

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

59 posts Page 4 of 4
IT TUNED!!!

I took the valve off, vial off, sonicated it in methanol for an hour, put it back on and pumped it down overnight. It passed tune Emvolts 1341. Still a bit of methanol in the valve. It indicated 10% oxygen 1% nitrogen so its obviously methanol.
MSCHemist wrote:
IT TUNED!!!

I took the valve off, vial off, sonicated it in methanol for an hour, put it back on and pumped it down overnight. It passed tune Emvolts 1341. Still a bit of methanol in the valve. It indicated 10% oxygen 1% nitrogen so its obviously methanol.
So, did you confirm it was a frit? I vaguely remember tech support warning me it had a fragile capillary tube inside.
Not sure I just took it off and the vial out and submerged the metal half with the valve in methanol and sonicated it for about an hour. It did appear to have a small tube or something on the vial end; the MS end there is just a small metal opening. Still some residual methanol in the valve despite purging it (tune gave 10% oxygen which is really methanol since they both weight 32 1% H2O and N2).

This time when I tuned it it went up to 1or2 E-4 and stayed at 4-5 E-5 Torr throughout the tune then returned to 1.9-2E-5 Torr at the end.
MSCHemist wrote:
This time when I tuned it it went up to 1or2 E-4 and stayed at 4-5 E-5 Torr throughout the tune then returned to 1.9-2E-5 Torr at the end.


Sticky valve aside, I'm not surprised that you had tuning issues at 10^-4 torr. That sounds WAY too high to me to get a reasonable number of ions through the quad.

All of that aside, I'm jealous of your 1.9x10^-5 :) . 2.5x10^-5 is about the best I seem to be able to manage on my 5975 at a .5mL/min He flow rate(the "rest" flow rate I use).
MSCHemist wrote:
This time when I tuned it it went up to 1or2 E-4 and stayed at 4-5 E-5 Torr throughout the tune then returned to 1.9-2E-5 Torr at the end.


Sticky valve aside, I'm not surprised that you had tuning issues at 10^-4 torr. That sounds WAY too high to me to get a reasonable number of ions through the quad.

All of that aside, I'm jealous of your 1.9x10^-5 :) . 2.5x10^-5 is about the best I seem to be able to manage on my 5975 at a .5mL/min He flow rate(the "rest" flow rate I use). I usually run 3.5-4x10^-4 during a "typical" 1 mL/min run(and that's the flow rate I use for autotune since that's the flow rate on probably 90% or better of the methods run on my instrument).
benhutcherson wrote:
MSCHemist wrote:
This time when I tuned it it went up to 1or2 E-4 and stayed at 4-5 E-5 Torr throughout the tune then returned to 1.9-2E-5 Torr at the end.


Sticky valve aside, I'm not surprised that you had tuning issues at 10^-4 torr. That sounds WAY too high to me to get a reasonable number of ions through the quad.

All of that aside, I'm jealous of your 1.9x10^-5 :) . 2.5x10^-5 is about the best I seem to be able to manage on my 5975 at a .5mL/min He flow rate(the "rest" flow rate I use). I usually run 3.5-4x10^-4 during a "typical" 1 mL/min run(and that's the flow rate I use for autotune since that's the flow rate on probably 90% or better of the methods run on my instrument).


Is that with the oil diffusion pump? I run in the mid 10^-6 range at 0.8 ml/min helium with the performance turbo on the 5975 and 5973, but definitely low to mid 10^-5 with my diffusion pump models.

What I can't get over is my 7000C running in the 7-8x10^-7 torr at 1ml/min helium. I couldn't believe the gauge was correct when I first got it.
The past is there to guide us into the future, not to dwell in.
James_Ball wrote:
benhutcherson wrote:
MSCHemist wrote:
This time when I tuned it it went up to 1or2 E-4 and stayed at 4-5 E-5 Torr throughout the tune then returned to 1.9-2E-5 Torr at the end.


Sticky valve aside, I'm not surprised that you had tuning issues at 10^-4 torr. That sounds WAY too high to me to get a reasonable number of ions through the quad.

All of that aside, I'm jealous of your 1.9x10^-5 :) . 2.5x10^-5 is about the best I seem to be able to manage on my 5975 at a .5mL/min He flow rate(the "rest" flow rate I use). I usually run 3.5-4x10^-4 during a "typical" 1 mL/min run(and that's the flow rate I use for autotune since that's the flow rate on probably 90% or better of the methods run on my instrument).


Is that with the oil diffusion pump? I run in the mid 10^-6 range at 0.8 ml/min helium with the performance turbo on the 5975 and 5973, but definitely low to mid 10^-5 with my diffusion pump models.

What I can't get over is my 7000C running in the 7-8x10^-7 torr at 1ml/min helium. I couldn't believe the gauge was correct when I first got it.


Yes, I have diffusion pumps on both my 5975 and on my Saturn 2100(the latter of which has some issues and is not currently in service as I don't want to buy an electron multiplier and throw other money at an instrument that would probably never get used). The 5971 I learned GC and GC-MS also had a diffusion pump.

My predecessor in my job and I have talked a fair bit about his decision to buy diffusion vs. turbo pumps on both instruments(he was the one who specced them). On one hand, I love the fact that I can basically forget that the pump is there. I should change the oil in the 5975 as it's getting close to 10 years old and I don't think it's ever been done, but will probably put that off until I blow another filament(when one of them goes, I switch over to the other one and schedule the down-time within a week or two to replace the blown one and clean the source). Our aging Voyager MALDI-TOF went through a spell of a nice turbopump diet, and I DON'T like the cost of having to replace it. Of the stuff I take care of, my LCQ Duo is the only thing with a turbo-you pretty much need a turbo with ESI/APCI(aside from the first gen commercial triple quads I once used with ESI/APCI that had cryopumps).

Even though they require a bit more maintenance than a diffusion pump, though, I love the fact that you can pump down a 597x in under ~30 minutes and can "recover" from stuff like the solvent peak a lot faster. In fact, I've been tinkering with a method for someone in the department the fast few weeks where the latter would be GREAT-they're monitoring a reaction in methanol, and there's still a pretty high methanol background when I turn the MS on and their main analyte can get "lost" in it-I'd actually do it as a SIM method were it not for the fact that they need to look at a handful of other things that elute later.

Also, during a pump-down cycle, Chemstation can somewhat buggy about accurately reporting the status of the diffusion pump accurately(i.e. whether its on or off and the current temperature of it) plus I feel like it's a good ~12 hours before results look good from it(even if it will tune well in that time). There's also the fact that it can be an hour before the pump has cooled down enough to safely vent the instrument after killing the rough pump and turning off the diffusion pump heater.

I got offered a SUPER nice 6890/5973N system with a turbo last week for a killer price, but the money just isn't there to buy it right now. I guess I can thank Rick Pitino for that one :)
benhutcherson wrote:
James_Ball wrote:
benhutcherson wrote:

Sticky valve aside, I'm not surprised that you had tuning issues at 10^-4 torr. That sounds WAY too high to me to get a reasonable number of ions through the quad.

All of that aside, I'm jealous of your 1.9x10^-5 :) . 2.5x10^-5 is about the best I seem to be able to manage on my 5975 at a .5mL/min He flow rate(the "rest" flow rate I use). I usually run 3.5-4x10^-4 during a "typical" 1 mL/min run(and that's the flow rate I use for autotune since that's the flow rate on probably 90% or better of the methods run on my instrument).


Is that with the oil diffusion pump? I run in the mid 10^-6 range at 0.8 ml/min helium with the performance turbo on the 5975 and 5973, but definitely low to mid 10^-5 with my diffusion pump models.

What I can't get over is my 7000C running in the 7-8x10^-7 torr at 1ml/min helium. I couldn't believe the gauge was correct when I first got it.


Yes, I have diffusion pumps on both my 5975 and on my Saturn 2100(the latter of which has some issues and is not currently in service as I don't want to buy an electron multiplier and throw other money at an instrument that would probably never get used). The 5971 I learned GC and GC-MS also had a diffusion pump.

My predecessor in my job and I have talked a fair bit about his decision to buy diffusion vs. turbo pumps on both instruments(he was the one who specced them). On one hand, I love the fact that I can basically forget that the pump is there. I should change the oil in the 5975 as it's getting close to 10 years old and I don't think it's ever been done, but will probably put that off until I blow another filament(when one of them goes, I switch over to the other one and schedule the down-time within a week or two to replace the blown one and clean the source). Our aging Voyager MALDI-TOF went through a spell of a nice turbopump diet, and I DON'T like the cost of having to replace it. Of the stuff I take care of, my LCQ Duo is the only thing with a turbo-you pretty much need a turbo with ESI/APCI(aside from the first gen commercial triple quads I once used with ESI/APCI that had cryopumps).

Even though they require a bit more maintenance than a diffusion pump, though, I love the fact that you can pump down a 597x in under ~30 minutes and can "recover" from stuff like the solvent peak a lot faster. In fact, I've been tinkering with a method for someone in the department the fast few weeks where the latter would be GREAT-they're monitoring a reaction in methanol, and there's still a pretty high methanol background when I turn the MS on and their main analyte can get "lost" in it-I'd actually do it as a SIM method were it not for the fact that they need to look at a handful of other things that elute later.

Also, during a pump-down cycle, Chemstation can somewhat buggy about accurately reporting the status of the diffusion pump accurately(i.e. whether its on or off and the current temperature of it) plus I feel like it's a good ~12 hours before results look good from it(even if it will tune well in that time). There's also the fact that it can be an hour before the pump has cooled down enough to safely vent the instrument after killing the rough pump and turning off the diffusion pump heater.

I got offered a SUPER nice 6890/5973N system with a turbo last week for a killer price, but the money just isn't there to buy it right now. I guess I can thank Rick Pitino for that one :)


Just noticed your location after the Pitino comment, we are only about 150 miles away :)

Diffusion pumps are also better if you want to use hydrogen carrier, they pump it out much more efficiently than the turbos do. I always let my diffusion pump instrument run overnight after venting before I even try to calibrate, even better to do maintenance on Friday and calibrate on Monday, otherwise I am calibrating a few days later due to the final stabilization over a couple days.

Turbo pumps shine if you are needing to run more than 1ml/min flow rates or have to clean the source often such as when doing 8270/625 waste water samples. I have to say though, in 27 years I have only had to replace two turbo pumps on Agilent MS, one 5970 and one 5973, and each was over 10 years old. We did have an ICP/MS that was eating them up quickly for a while, but other than that no problems with them.
The past is there to guide us into the future, not to dwell in.
The 10-4 is just the initial jump after the valve opens. It stays arround 5E-5 during the tune now. It may have some air left in there despite me purging the calibrant valve.

Really? I attended quite a few hydrogen conversion seminars several years back and I remember Agilent saying not likely to work well with a diff pump system. I assume if you use a narrower bore column (<0.18mm) to reduce the gas flow you would be ok on whatever system. I gave up on hydrogen. It sounded like a lot of trouble and I rely to heavily on very sensitive library matches. Trying to get my MSD to differentiate terpene compounds is tough enough with helium expecially the C15H24 selinenes, cubebenes, copaenes, caryophylenes....

Yea I'm just happy to finally have my instrument working.
Good to know it really was just the detector and that you did not have to buy a side board. Speaking of turbo pumps, we got our 5973 in 2004 and about 7 years later had to get the turbopump rebuilt. Then we had to rebuild it again 2 years later in 2013. I hope I can get 10 years out of this one. Mine is a BOC Edwards standard turbo.

Edits: I went and looked this up in the maintenance log. Our turbopump failure rate has been worse than I remembered.
James_Ball wrote:
Just noticed your location after the Pitino comment, we are only about 150 miles away :)

Diffusion pumps are also better if you want to use hydrogen carrier, they pump it out much more efficiently than the turbos do. I always let my diffusion pump instrument run overnight after venting before I even try to calibrate, even better to do maintenance on Friday and calibrate on Monday, otherwise I am calibrating a few days later due to the final stabilization over a couple days.

Turbo pumps shine if you are needing to run more than 1ml/min flow rates or have to clean the source often such as when doing 8270/625 waste water samples. I have to say though, in 27 years I have only had to replace two turbo pumps on Agilent MS, one 5970 and one 5973, and each was over 10 years old. We did have an ICP/MS that was eating them up quickly for a while, but other than that no problems with them.


Yes, I'm at the big red school :)

In any case, the comment about H2 and diffusion pumps is interesting. I'll have to spend some time thinking through that one-I could see it being a case of the H2 molecules being too small for the blades to "catch" them effectively.

I too have been to some Agilent seminars on using H2, and I'm sold on it although I haven't tried it. The Saturn is a likely candidate if I ever get it going again. Aside from needing a new electron multiplier, its rough pump is currently in service on my 5975 while I wait on our scientific instrument tech to rebuild the pump that came with that instrument. Since the mass spectra from that instrument always have and always will look weird relatively to library spectra(thanks to it being an ion trap and not a traditional quadrupole), I don't think it would matter too much for that instrument.

There again, I'll go back to the fact that I've never dealt with an Agilent MS with a turbo pump, so don't know anything about their reliability. I've actually been keeping my eyes open for a 5970 for a couple of reasons, not the least of which is that they're quite inexpensive these days, although I don't know if it would be a great investment for me unless the price was free or pretty darn close to it. There's an out of service 5890/5971 in the department that I've asked about, but the owner isn't QUITE ready to let it go(and I think it's a diffusion pump-not sure if I've ever seen a 5971 with anything else).

Our MALDI-TOF is a bit of an interesting case. It's closing in on 20 years old, and you could probably count the time it's been open/vented in that time period in days. Even though-in theory-keeping an MS under vacuum is one of the best things you can do for it, that much time does take its tole on an instrument. We actually have two identical units sitting in the room with it-one is PROBABLY good enough that we could actually put it into service(it will pump down to where it should go, and the laser is strong) but hasn't actually been tested since we don't have a spare computer to connect it to and really don't want to disturb the working one. With that said, the top turbo pump(the one attached to the reflectron) has a TERRIBLE whine on the in-service instrument, and one of the PIs who looks after the instrument doesn't want to change it until it dies completely-if it were me I'd rather go ahead and stick a known good one on it since-with the way it current sounds-it's not an "if" but a "when" it goes. That's really outside my jurisdiction, though-I just advise/assist when something does break on it.

Unfortunately too for me, ANY maintenance(scheduled or unscheduled) on the GC-MS is a problem. Some PIs and grad students expect 25/8/366 availability of the instrument and can get really upset if it's down. It was enough of an issue that my predecessor finally told one to buy his own. He bought an identical 7820/5975, but now they STILL want use mine because they can't be bothered to do basic maintenance(they've called me about problems before, and I've pulled out inlet liners that I was halfway tempted to save because I've NEVER one look so bad-and they don't even realize they're there-much less doing things like source maintenance on it). I also have another faculty member who constantly brags about how "wonderful" his Thermo GC-MS is and about how it can "see things you can't see on an Agilent." I suspect that if he ran his samples on MY 5975 and not the other(poorly maintained) one in the department it would do just as well, but that's something not worth fighting.

In any case, where I was going with that I'd rather do service during the week where I can actually monitor it and actively keep people away from it even if I'm dealing with a barrage of "when will it be ready again?" If I did maintenance and then a pump-down on Friday, people would try to use it Friday night or Saturday and then complain about how bad their results were. That's also why I want another instrument that's at least reasonably similar(specifically a 597x instrument)-the spectra should be close enough to the 5975 that they can compare their results, and of course both would have a 30m/.25mm HP-5/DB-5/whatever-5 column.
I had good results with hydrogen except for trying volatiles where it is next to impossible to hit the BFB tuning criteria as the hydrogen causes the 95/96 ratio to be out of spec. Hydrogen is attaching to the 95 and making 96 too abundant. For semivolatile 8270 it would tune just fine. The worse thing is having to wait a month for the hydrogen to clean all the crud out left by the helium, it literally took a month for the hydrocarbon background to drop to acceptable levels as the hydrogen scours the entire flow system and pulls out any trace of oils in it.

I went to 0.18 columns a long time ago for all of our GC/MS instruments due to people always asking for lower detection limits, and it gives shorter run times. Most systems are still on helium since we have the 5975's with the wrong magnets for hydrogen and I don't want to go to the trouble to replace them.
The past is there to guide us into the future, not to dwell in.
I hadn't even considered going to a .18mm column-that's a good idea, although I can't really change it on 7820/5975 since there are far too many PhDs at stake if I used anything other than a 30m/.25mm -5 column. Once again, another reason for me to try and get the Saturn going again.

I was digging around today and did find an interesting blast from the past-an HP branded 50m/.320mm CW20M capillary column. I may test and then install it in the 5890(FID) that I've finally been able to bring back to life. Our main column in our little Buck/SRI instruments is 6ft/1/8" packed CW-20M. One of our upper level courses does an experiment where the construct a Van Deemter plot on those instruments, and the plan this year is to expand the experiment to have them also run the same samples on a capillary column GC(the 5890). I'd planned to buy a 30m/.25mm CW-20M capillary so they could work with the same stationary phase across both instruments, but assuming this one I just found is good I can save having to buy one.
James_Ball wrote:
we have the 5975's with the wrong magnets for hydrogen and I don't want to go to the trouble to replace them.

Agilent replaced my magnet for free as a warranty repair several years back. Not much trouble the magnet is [ shaped and the top I believe is only held to the rest of the magenet magnetically so it pulls off and you just swap out the magnet and pump back down.

I am going to put the ETP detector on my 5975 since I have it even though at 1900ev I can easily squeeze another few years out of the OEM detector. At 1350ev no reason the change the one on the 5973.
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