Chromatography Forum

First of all I do not work in a Laboratory anymore. I used to work in an environmental lab and hated it, so I got into the controlled atmosphere biz. I now work in a shop and my boss wants me to set up a GC. Someone else was ordering gas and I was working on setting up this GC so I told him to get me HE an H2, without clarifying that I needed high-purity gas.

So I bought HE and H2 gas a couple weeks ago. and just looked at it and it's industrial grade. I'm a moron for not making sure that I got pure gas. So anyway I'm stuck with this gas, Is it usable? Do I need to bite the bullet and admit to my boss that I got the wrong gas? Do you think they would take it back since it hasn't been used? Setting up this GC is one thing after another. I'm so sick of it.

There should be purity recommendations in the GC manual. We use 99.999+ stuff for the most part. I wouldn't risk using them. You could:

-waste the gas the you could possibly return.
-mess up your in-line filters.
-mess up on-board filters.
-get your detector dirty.
-wreck a column.

Just trade those in, or buy new cylinders

You might get away with using the hydrogen for the FID but there is no way I would ever put industrial helium through a GC column. Throw a party and use the helium to blow up the balloons - that's about all its good for.

Peter

Just call the gas vendor and tell him you messed up. They will probably have no problem swapping sealed cylinders for full credit, especially if you're a newer customer.

Vox,

DR is correct, if the seals are not broken you should be able to return the cylinders but you will pay for shipping and the better grades of gas will cost you more. If the seals are broken and your boss would be mighty upset, one option to consider, especially since you are using packed, is to use the hydrogen as both carrier and FID gas. With packed, you probably could blank off the connector to the FID manifold and just use the carrier hydrogen to feed the flame. Hydrogen should be cleaner than industrial grade helium.

Best regards.

Obviously, the preferred option is to return to supplier. but if you can't return, then ensure you have suitable traps in the lines, especially for oxygen and moisture.

Look at the specification for the Industrial grade, and compare against the instrument grade. You may be able to use it if you have to.

I used Industrial grade hydrogen and helium for 20 years as carrier and detector without any major issues, just because the gases were already reticulated around the building, and we had purgeable cylinder changing. If you have appropriate traps, industrial grade works fine for most applications.

I'm slightly bemused seeing instrument and UHP grades cylinders being connected to high pressure manifolds that don't have purges, or even isolation valves, allowing air into the system.

Please keep having fun,

Bruce Hamilton