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Compressed Argon Gas Contamination

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fcl54643

Contributor

Posts: 21

Joined: Mon Nov 02, 2015 2:13 pm

Location: Greater Philadelphia Area

Post Thu Jun 23, 2016 4:20 pm

Compressed Argon Gas Contamination

Hi everyone,

We have had some serious difficulties obtaining reliable argon gas supply from our gas supplier that have hindered our ability to use our CyTOF2 reliably since its installation in our current facility. Initially, we were ordering liquid Argon (Ultra High Purity grade), however the Xenon contamination was often not acceptable. We then switched to compressed gas, hoping it would improve the quality of our supply (99.9995% TG AT, Trace Analytical Grade, AR 5.5). Unfortunately, the reliability of our supply is still questionable...

A new issue arose the last couple of days, where a new contaminant was noticed in our new batch of compressed gas argon (supposedly 99.9995% TG AT, Trace Analytical Grade, AR 5.5). As Fluidigm was not able to indicate what the contaminant was, I was wondering if one of you had encountered it before. Attached is a PowerPoint slide with screenshots of TOF and Acquisition windows. When we switched to another batch of argon supply, the contamination seen in the windows was gone.

Would any of you had this type of contamination before?

A few points to note:

- We are not allowed to switch to a different gas supplier, so this is unfortunately not an option.
- We are using a manifold and a gas pipeline across the lab to reach the instrument. This line/manifold is solely connected to our argon supply.

I really would appreciate your insights on this and any tips on best argon supply practices.

Thank you,

Florence
Attachments
06232016 Argon Cylinder Contamination.pptx
(439.96 KiB) Downloaded 415 times
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mleipold

Guru

Posts: 2086

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Thu Jun 23, 2016 5:22 pm

Re: Compressed Argon Gas Contamination

Hi Florence,

I haven't seen contamination in this range before.

However, based on natural abundance distributions here: http://www.chem.ualberta.ca/~massspec/a ... _abund.pdf

It looks like it might be Krypton impurities:
78Kr: 0.35%
80Kr: 2.28%
82Kr: 11.58%
83Kr: 11.49%
84Kr: 57.00%
86Kr: 17.30%

The height of your peaks at least roughly matches this distribution, though the 86Kr signal looks a bit too high in the Praxair lots 8000 and 7886 (though it looks correct in lot 7060).


As Krypton (like Xenon) is a noble gas, I can imagine the supplier could have issues separating it away from Argon. But I've never seen this contamination in any of my argon tanks (cylinder or liquid dewar).


Mike
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fcl54643

Contributor

Posts: 21

Joined: Mon Nov 02, 2015 2:13 pm

Location: Greater Philadelphia Area

Post Thu Jun 23, 2016 5:34 pm

Re: Compressed Argon Gas Contamination

Thank you, Mike! I have requested pick-up of those cylinders as I cannot possibly run any samples with that level of contamination...

Best,

Florence
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AdeebR

Grand master

Posts: 171

Joined: Thu Mar 13, 2014 5:58 pm

Location: NYC

Post Thu Jun 23, 2016 5:44 pm

Re: Compressed Argon Gas Contamination

Hi Florence,

That looks pretty bad. I agree with Mike's Krypton suggestion but also have never seen this before.

I'm curious how bad your previous xenon contamination was with the liquid argon. This hasn't been an issue for us in the past, but our last couple of tanks have had relative high levels of xenon contamination. Trying to discuss and resolve this issue with our gas supplier has unfortunately been completely futile.

Adeeb
Adeeb Rahman
Icahn School of Medicine at Mount Sinai, NYC
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fcl54643

Contributor

Posts: 21

Joined: Mon Nov 02, 2015 2:13 pm

Location: Greater Philadelphia Area

Post Thu Jun 23, 2016 6:23 pm

Re: Compressed Argon Gas Contamination

Hi Adeeb,

Our previous Xenon contamination with liquid Argon was high enough that it did not pass mass calibration unless the range was modified. It has been a constant fight with our supplier for months. My next step is to convince them to buy brand new cylinders and reserve them for our use only, as well as insisting that they pressurize and depressurize thoroughly prior to refilling. Providing I am able to move forward with that plan, I will let you know how it works out for us.

Florence
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EHaasDFCI

Contributor

Posts: 24

Joined: Thu Jun 15, 2017 5:34 pm

Post Fri Oct 05, 2018 7:46 pm

Re: Compressed Argon Gas Contamination

Hi Everyone,

I was just wondering if anybody had anything to add about obtaining better quality liquid Argon? We've been having a tough go lately with our liquid Argon supplier and switching to compressed gas seems like an un-realistic option given our volume of use. Any suggestions other than switching tanks with the supplier?

Thank you,
Eric
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mleipold

Guru

Posts: 2086

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Fri Oct 05, 2018 8:26 pm

Re: Compressed Argon Gas Contamination

Hi Eric,

What's your current liquid argon problem? High Xe levels? High Kr levels?

Or are you seeing true contaminants in it, like Sn?


Mike
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FlowjoVA

Participant

Posts: 12

Joined: Tue May 24, 2016 4:49 pm

Post Fri Oct 05, 2018 10:07 pm

Re: Compressed Argon Gas Contamination

Hi Eric:
We had lots of problems finding a vendor that could provide us with clean enough Liquid Argon (mostly was Zenon issues). We went as far as paying extra for them to flush the tanks 10 times before refilling and giving us dedicated tanks, but that didn't solve the problem either. We finally found a company (Arc3 Gases) that dispenses liquid gas from the top of their large reserves tanks, rather than from the bottom (which is what most of the others do). The Zenon is heavier and settles to the bottom so this is where the problem lies (literally). Since switching to the top filling company we have not had the same problems.
Hope this helps!
Best,
Joanne
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mleipold

Guru

Posts: 2086

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Fri Oct 05, 2018 10:23 pm

Re: Compressed Argon Gas Contamination

Very interesting Joanne......thanks! It's also consistent with what we've observed: we often get a spike in Xe signals if we completely drain a liquid tank.


When the Bay Area had the Xe contamination about 18 months ago, Praxair (the affected supplier) advised us to switch grades.

We had been ordering AR4.8 LC-230-230 tanks. Those were the ones that got contaminated. They had been convenient because Praxair would generally get it to us next-day.

They suggested that we switch to ICP-grade AR4.8-IC230-230 tanks (IC, not LC). They said those are certified Kr-free because of use as inert atmosphere in microchip production (Kr-lasers are used to etch). For us, we didn't care about Kr specifically, but the fact that it was drawn from a completely different supply tank. The downside was that those tanks are 3-4 day delivery, so it makes argon supply management harder.


Note: when the Xe contamination happened, a few weeks later, the compressed AR5.0UH-T cylinders were *also* contaminated. That's because they filled those from the same supply tank as the LC230.


Praxair does not have a spec on Xe; based on my calculations back then, it's not even clear they *could* get a purity spec.....the CyTOF is just really sensitive!


Mike
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takuya

Participant

Posts: 1

Joined: Fri Jan 23, 2015 5:04 pm

Post Mon Oct 08, 2018 3:25 pm

Re: Compressed Argon Gas Contamination

Hi all,

We, at the University of Pennsylvanian, are seeing very high Xenon in Argon gas these days too. Multiple tanks from Airgas. We are considering purchasing higher grade gas, or switching supplier. The problem is higher grade gas cost $100 more per 160L tank, which is not a small cost increase. But according to the posts here, changing supplier does not solve the problem unless they fill only from the top of the bulk tank? Any suppliers guarantee the quality of their product at the consumer level?

Thank you,
Takuya
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