Agilent 6490 QQQ capillary cleaning

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

28 posts Page 2 of 2
I have not actually been following the recommended source cleaning cycle at all... :oops:

I haven't had any specific problems of sensitivity loss... but I guess I'm just afraid that I'm too clumsy to clean the source regularly without breaking something.
We run urine in our 6460s and 6490s. In both cases it's mostly dilute and shoot. The 6460s have been running well with minimal downtime. The 6490s are a different story.
MX304 wrote:
We run urine in our 6460s and 6490s. In both cases it's mostly dilute and shoot. The 6460s have been running well with minimal downtime. The 6490s are a different story.


Yeah, we run food and dietary product extracts which do have some sample prep but are probably dirtier than your average dilute and shoot. It's the column I usually have to remediate most often (backflush the guard when peak shapes degrade). MS is fine. It's just very sensitive to matrix effects. I hear that the 6460 is more so than others.
We have an Agilent 6530 and have also been struggling with sensitivity due to contamination of the glass capillary.

Interested to see a couple of comments here where users prefer the plain glass (dielectric,non fast switching) capillaries over the "frosted" (resisitive,fast switching) capillaries.

Is that from direct experience that the plain glass ones stay cleaner longer?

Also any more tips/suggestions how to successfully clean these capillaries would be most welcome!

Thanks

Ian
for our 6460 at the end of every batch there is a flush method (120 minutes) of 100% organic solvent cleaning, with ms in standby (divert valve in MS of course)
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daniele
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I'm late to this discussion, but my observations are that we have seen better sensitivity with the older glass capillaries (on a 6224 TOF instrument) than the resistive capillary, but my sense is that we are seeing sensitivity issues sooner with the glass ones relative to the resistive type. It seems that the drop of signal is a perennial problem and I have resigned myself to buying new capillaries as needed, since the Alconox cleaning, in my experience, does not do much besides waste time (it's very effective for that purpose).

I am going to try the "drop of MeOH, drop of IPA" method-- is there consensus here that that is the best way to clean the capillary?
Looks like the thread is pretty old. I'm not sure if you are still interested.

A while back, a customer mentioned the problem of cleaning those capillary tubes to me in a random conversation. I was brave enough to throw it at our technical services team and have their bald heads scratched. They found that the cleaning procedures from the manufacturer, if successfully carried out, can only take care of loose "dirt". It's inevitable that the capillary gradually loses its transfer capability because of accumulated contaminants hardened by high temperatures.

They also came up with a cleaning method and tried on a tube from the customer. The process was slow but actually worked. The customer was able to use the cleaned capillary tube and use it for many months.

Will you be interested in having us cleaning your capillaries? The contact info can be found from ardst.com.
So glad that I found this thread. I have a 6490 QQQ and I find that it is incredibly sensitive!! I love it. I have been running intracellular (bacterial), targeted metabolomics on a specific type of analyte. Trace analysis. I have been having trouble with losing 10x sensitivity after only 100 injections of samples. Only injecting 2 ul, and have been fastidious about keeping the source clean. Anyone else out there running bacterial intracellular analysis who has tips on maintaining sensitivity through a specific cleaning protocol? It is important for me to maintain as high of sensitivity as possible, obviously, because my compounds are present in the nM range and I need to report highly accurate values. Looking for any advice that I can get. My gut feeling is that although the hexapore capillary increases the amount of ions that get through to the quads resulting in incredible sensitivity, it probably also increases the amount of garbage that also gets through.

Thanks so much in advance!!
Hey JamieAlison,

I'm sorry but i can't answer your question. However, thank you for reviving this old topic i've been reading it with great interest. Our lab is buying a new LC-MS soon, and I have been organizing demos and comparing different vendors. The 6495B is one instrument that is on the shortlist. Sensitivity drops over time is unfortunately something you can't check in a demo.

If there's anyone with up-to-date info about the 6495B concerning this issue (or if there are no issues), that'd be great information for us.
mty wrote:
Hi Aviator,
We had our service tech in (whom I love!) and she said that very thing. We learned how to clean the optics. She also recommended the droplet of 50:50 MeOH:DI or 50:50 isopropanol:DI. We have also moved away from the resistive capillary, back to the glass capillary. Our responses are not exactly what we'd like, but they are reasonable. I'm SO happy to hear that someone else had a rough first year with this instrument!

Camisotro, I think if cleaning the source does not return your sensitivity, then it is time to dig deeper into the optics.
One tip we got was to suspend the nebulizer in a beaker of 50:50 MeOH:H2O while the instrument warms up and stabilizes, to prevent any baking on of salts. Come to think of it, we've gotten quite a few tips from our tech that are about flushing/rinsing/washing....I see a trend. :)

We haven't had enough good runs to notice significant decreases in response over the course of the run--but maybe. I'd have to go back into some data.

We are using an ammonium acetate buffer, and that seems to be a significant part of our problem, too.

All SPE is off-line--sorry, don't remember who asked that.
Thanks so much for all your comments! I'm usually just a lurker, but I learn a lot!
mty



Hi mty
The last few weeks, I am also struggling with our 6460C. After an Autotune failure, I had to “Tune from factory defaults” to pass all tests (all parameters green). I initially thought of the multiplier, but it seems to be fine (it remained at 1160 volts after Autotune). Though, it seems that 6460 is not able to maintain itself tuned for more than 24hours (maybe less but I haven’t checked that). In the following days, Checktune was taking quite much time to finish and there were always some MS Parameters outside the limits, particularly for m/z 322 (in the positive mode). I also noticed a strange behavior in my LC-MS/MS runs (dynamic MRM), where specific MRMs provided zero signal even for standard solutions at ng/uL level, while some other MRMs showed some decent peaks! Having limited experience with 6460 and reading the posts on this topic, I finally realized that after 230 injections (the last 30 injections with 2mM ammonium formate + 3.6mM formic acid in the mobile phase), the system should be contaminated. I decided to clean the capillary, but I am afraid that I will have to go clean deeper in the skimmer and possibly ion optics (ouch!!). This is too much downtime (time lost to realize the problem and time lost to fix it) and the first signs of disappointment for Agilent are creeping in my face. At least, I am thinking to buy 1-2 spare capillaries to save some time. Is there a final consensus about the robustness of the different capillaries? You and Aviator seem to prefer the old glass capillaries (dielectric, non fast switching), while cutlersr suggests that these are getting dirty faster compared to the new, resistive ones (fast switching capillaries). I would appreciate to get an update about your experience with dielectric vs resistive capillaries and if you have noticed a clear advantage for one or the other in terms of robustness.
Thank you
I am interested to hear about these capillaries also. We are looking to purchase a 6470(since the 6460 is nearing its end of life very soon). It would be our first Agilent so need to know if there are things to watch out for. Our current LCMSMS is the ABI 3200, very simple to clean, normally just use a micro syringe cleaning wire to slide through the inlet cone orifice when sensitivity drops and everything is right back to normal.
The past is there to guide us into the future, not to dwell in.
James_Ball wrote:
I am interested to hear about these capillaries also. We are looking to purchase a 6470(since the 6460 is nearing its end of life very soon). It would be our first Agilent so need to know if there are things to watch out for. Our current LCMSMS is the ABI 3200, very simple to clean, normally just use a micro syringe cleaning wire to slide through the inlet cone orifice when sensitivity drops and everything is right back to normal.

Hi James,
You mentioned that your 6460 is nearing the end of its life. Is there a specific reason to say that (e.g. turbo-pumps?, electronics? defective quads? unstable signal? other?)? I would really like to hear what kind of problems have led your system to the end of its life and if there is any special practice we should follow in order to extend the life of our new 6460C.
Thank you in advance for sharing your experience.
manman
manman wrote:
James_Ball wrote:
I am interested to hear about these capillaries also. We are looking to purchase a 6470(since the 6460 is nearing its end of life very soon). It would be our first Agilent so need to know if there are things to watch out for. Our current LCMSMS is the ABI 3200, very simple to clean, normally just use a micro syringe cleaning wire to slide through the inlet cone orifice when sensitivity drops and everything is right back to normal.

Hi James,
You mentioned that your 6460 is nearing the end of its life. Is there a specific reason to say that (e.g. turbo-pumps?, electronics? defective quads? unstable signal? other?)? I would really like to hear what kind of problems have led your system to the end of its life and if there is any special practice we should follow in order to extend the life of our new 6460C.
Thank you in advance for sharing your experience.
manman


We don't have the 6460 but were looking at one to purchase. Agilent has said they are discontinuing this model at the end of the year so that will mean end of parts support in 10 years or less. We are instead looking to purchase the 6470 as it will have a longer support life. Our current LCMSMS is an Sciex API3200 which is now 12 years old, still running strong but no sensitive enough for the newer methods and testing we are planning to do.
The past is there to guide us into the future, not to dwell in.
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