Agilent 6490 QQQ capillary cleaning

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

28 posts Page 1 of 2
Anyone have a better solution for cleaning the capillary for an Agilent 6400 series triple quad? We have been using the Agilent recommended method of sonicating them in (1g of Alconox in 100ml water) then sonicating in Methanol. It's just not getting them clean enough. Any ideas?
I use another model and non agilent,
Flush the cappillary with H2O:IPA (50:50) by using 1000 ul pipette tip and Acetonitrile 5-10 ml continuously, blow it dry with N2 gas
Jetjamnong
Thanks. I'll give that a try.
do you have the 6-bore capillary? Let us know if it works.
Thanks
Loekie wrote:
do you have the 6-bore capillary? Let us know if it works.
Thanks


Yes, it is the 6-bore capillary. As soon as I have to clean another one I will report back.
Agilent 6410 and 6460 here. I dont switch off ms/ms just allow detector to pull in one droplet of methanol and one droplet of izopropanol. Works fine for me.
Pepter wrote:
Agilent 6410 and 6460 here. I dont switch off ms/ms just allow detector to pull in one droplet of methanol and one droplet of izopropanol. Works fine for me.
Interesting. Do you just open the source and introduce the droplet directly into the end of the capillary?
I pull down the temepratures before... like for normall source cleaning.
The Agilent cleaning method is pain...sometimes its rally hard to pull out the cappilary, every time you do this you scratch platinum ends another problem is that you need to switch of detector so time consuming and not good for turbo pumps.

Pesticides analysis in food here, QuEChERS extraction method.
As far this way of cleaning works good for us.

p.s.
sry for my english
Pepter wrote:
I pull down the temepratures before... like for normall source cleaning.
The Agilent cleaning method is pain...sometimes its rally hard to pull out the cappilary, every time you do this you scratch platinum ends another problem is that you need to switch of detector so time consuming and not good for turbo pumps.

Pesticides analysis in food here, QuEChERS extraction method.
As far this way of cleaning works good for us.

p.s.
sry for my english



Yeah I am not a fan of the spring capture design chewing up the platinum. Agilent dropped the ball with that design.
Hi Pepter,

I don't know how clean the extract is with QuECHeRs, but do you find you have to clean your system a lot? We have a 6460, and we've had a lot of problems with getting it up and going. Now that we have, it seems like we can only get a very few runs done before our sensitivity drops like a stone. Our matrix is urine, run through SPE before injection, so we were not expecting this problem. What is your maintenance schedule like? Do you have to clean the ion optics very often?

Thanks!
M
Hi
I dont have any experience with urine analysis. Duno how i can classify QuEChERS extract in "dirty table" compare to your samples.

We have two Agilent detectors in our lab. The oldest one is the 6410A. It comes to lab with MMI-source ... i change it to simple ESI source (this kind of combined ESI/APCI sources are mistakes for me - hard to clean, problems with sensitivity). From that up to now i really dont have any big problems with this detector ... the cleaning procedure looks like i write before. Standard for source chamber (like in Agilent maintance guide) and droplet for cappilary. You ask about ion optics...i done it like 4 times and not because of sensitivity drop, just for pratice while machines where down due to mainboard problems/turbo pump change etc.
Second detector the one you use is like 2 weeks in our laboratory we are on pesticide optimizing step for MRM method and as far only software problems occure.

Can you write some details about your extraction procedure, solvents and setups on lc-ms/ms ? Iam sure that we have here on forum some people that works with urine on Agilent detectors.

If i have simmilar problem to you i would:
1) find the part in ion source/optics thats is most resposible for sensitivity drop while getting dirty
2) check/optimize the temperatures of drying and sheat gas
3) work on extraction procedure (maybe chance to dilute sample ?)

p.s.
What kind of problems you have with 6460 ? Would be nice to know what i can expect from this machine.
mty wrote:
Hi Pepter,

I don't know how clean the extract is with QuECHeRs, but do you find you have to clean your system a lot? We have a 6460, and we've had a lot of problems with getting it up and going. Now that we have, it seems like we can only get a very few runs done before our sensitivity drops like a stone. Our matrix is urine, run through SPE before injection, so we were not expecting this problem. What is your maintenance schedule like? Do you have to clean the ion optics very often?

Thanks!
M


Hi mty, I use a 6460 for detecting pesticides in water. We had a lot of trouble with it in the first year but it's finally settled down (all that trouble did allow us to become quite the experts in fixing most problems however!).

There are several reason that could be causing your drop in sensitivity but to be honest, it sounds like your sample matrix is contaminating your ion optics. Due to the nature of our samples, we have to clean the ion optics at least once a month (although it has been more frequent than that in the past, during a bad batch of samples!). We too experienced that we could only do a few runs before the instrument started drifting or losing sensitivity rapidly, the sensitivity issue seems to be easily resolved by cleaning the optics but it can be a pain to do that often (not to mention you risk breaking it each time you do it).

Also, do you find that your sensitivity can drop steadily, but significantly throughout a run? We had this at one point, it was affecting our internal standards. If you're experiencing this, it's likely because your capillary is building up a charge. This can be reduced by switching the charge that goes through your capillary at the start and the end of each run (for example, if you're running in positive mode- have a time segment that runs in negative mode at the start and end of each run). Perhaps more significantly, look at the quality of your buffer. The 6460 in particular is *really* sensitive to poor quality buffer as we've found out in the past (it's a great instrument once it settles down, but everything you put through it bar samples should be at the very least, 99.9% pure).

You mention you run the urine through SPE before hand, is that offline SPE or using the online SPE module the instruments come with (at least ours did)?

Cheers,

Aviator
On a 6460, what would lead one to judge that the ion optics need cleaning as opposed to the source? An inquiring mind in charge of a 6460 would like to know.
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
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, I'm glad I could help :)

You'll probably be glad to know that the vast majority of my problems were also caused by our ammonium acteate buffer. The trick to getting past this is to use LCMS grade quality buffer which is 99.9% pure (our previous stuff was 99.1% pure which is a huge difference for the 6460). To keep your buffer pure, only use LCMS grade quality ammonium acetate and sources bottles small enough that you can only make a single batch of buffer before you have to throw out the bottle (that prevents the bottle from becoming contaminated). If you have any other standards or mobile phases with a poor buffer, I recommend you throw it all out and start again with a purer buffer!

With all LCMSs (but particularly the 6460) quality of your reagents and solvents is key. Anything less than LCMS grade will ruin it (trust me, I learnt the hard way). Buying solvents and regeants cheaper than LCMS grade is ultimately a false economy.

I'm quite fond of the 6460 but it's been emotional. Whilst I think it's a good instrument and capable of producing some good results, it is not the workhorse that Agilent likes to think it is. This is a view shared by some of my other contacts within my industry as well. It can work in an industrious way, but you have to have an intensive maintenance schedule to keep it tip top.

Moving back to the glass capillary is a good move- we also switched back to the glass capillary away from the resistive one.

This is an instrument which will probably teach you a lot as it has with me. If you're interested, I'll be happy to exchange contact details so we can bounce ideas off each other in the future.


EDIT: I see you said your SPE is offline. If you do any method development in the future, I'd strongly recommend looking at using the online spe module. We've only just started but the improvement is quite noticable and we're regretting not having used it from the start. Having said that, we were/are doing direct aqueus injections which agilent said would be fine with potable water (it's not fine).

Camisotro wrote:
On a 6460, what would lead one to judge that the ion optics need cleaning as opposed to the source? An inquiring mind in charge of a 6460 would like to know.


To echo what mty said, once your source cleaning stops working it's time to crack open the instrument and play around with the optics! There's not really much more to it that I'm aware of.
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