Chromatography Forum

Hello

I'm wondering if anyone is experiencing quality issues with Helium lately. We get UHP Helium from Air Liquide and it seems like one out of three G cylinder tanks have too much nitrogen. We have ruled out any leaks from the three GC/MS instruments and changing the tank always resolves the issue. This last tank we got shows Nitrogen at 15 - 20% with hardly any O2 or water.
Our service engineer told us a lot of his clients are accepting N2 percentage up to 20 nowadays. I'm getting pushback from Air Liquide who claim there must be something wrong on our end because they can't possibly have that many "bad" tanks.
Anyway I'm curious what everybody else is experiencing.

TIA
Mike - Phoenix, AZ

My issue has been excess argon in helium tanks. I've had a few of those in the last year or so. Haven't noticed a nitrogen issue.

AL is careful not to include N2 specs on their ALPHAGAZ branded helium. If you need an N2 spec, they are going to try to make you pay a premium for EG (electronic grade).

I was a QC chemist at a specialty gas fill plant for AL about 8-9 years ago, but since then I think they moved away from UHP/research branding.

Let me add (from my experiences as an analyst there) -- it is very easy to add nitrogen with poor cylinder changeout, poor line purge, or very slight leaks (including in the regulator itself). You have already ruled that out with your low O2 and moisture thankfully.

I have been buying bottles from Praxair and haven't noticed any issues, though to be honest it is doubtful that I would notice 20ppm nitrogen on my TCD.

We seem to have more problems since they started bottling the He in Phoenix. It used to come from some place else. And I was told they do not test for N2. So now they suggest we get the research grade at higher cost. Which I have to resort doing.

regards
Mike

Have you considered going with a different vendor? Is that a possibility?

Have you considered going with a different vendor? Is that a possibility?

No we don't get a choice, we have to use what the hospital uses which is AL. The hospital may change venders when the contract comes up for renewal though. I can only hope.

Mike

A few months back we had several from Weldstar/Purity Plus two that had grievously high amounts of argon and a third that had high amounts of nitrogen. They had to switch to a new labeling system that was compliant with global harmonized SDS and they apparently mixed cylinders. The last few have been fine.