What's in YOUR solvent tank (today)?

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So rather than derail yet another thread with the latest value I can turn on my CLS, I figured I’d start yet another thread…

@pdxcanna That is from my working solvent.

Refills are 30:70 propane:butane. Not supposed to be any iso in there.

We tried tracking blend with pressure, and the superheat in the non-ideal gas above our liquid solvent, or atmosphere that we’re accumulating from somewhere (more likely) made that unreliable.

We are just refilling with 30:70 and seeing where we land. So I had to figure out where we landed…

The injections shown are both 1:10,000 dilutions with atmosphere.

In addition to the isobutane I’ve got at least three other peaks I need IDs on when I inject a 1:10 dilution

hmm, is a 1:10 dilution of flammable solvent into a stream of H2 a good idea?

What’s the UEL again? The LEL?

How do I know its iso butane?

I’m making an educated guess after injecting a standard :wink:

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I found this.

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Following the logic wouldn’t propene elute to the left of (prior to) propane?

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This is the source. Couldn’t get a clean hyperlink.

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https://www.researchgate.net/figure/Separations-on-column-I-Chromosorb-R-NAW-10wt-97-PTMSP-3-PPP-a-C1-C8-hydrocarbons_fig2_326088000

That might be a different column though but it follows the same logic I presented.

See peaks 5,6

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Thanks.

Yep, that IS a different column, and method.

I’ve got a benzene, but would rather not start spreading ppb around the lab.

That peak is the largest mystery peak, but there are atleast a couple of others that show up in the higher loadings.

Starting with the COA for the input gas was going to be my first approach.

@srihugh1 might also have C1-C18 hydrocarbon data on the Hayes D column I’m using.

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It sure looks like you’re on to something.

Is your hypothesis that butane or propane is being isomerized to iso, or that the origin fill tank gas is contaminated with iso?

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I would lean towards this.

But I’m a laymen, so not saying much

Lol

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Me too, but sometimes I learn something asking🤷‍♂️

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How about, unexpected.

“Contaminated” is perhaps a stretch for that and neo-pentane.

(Test your beer for methanol…)

So long as they don’t contain benzene…

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Propylene would make sense as a contaminant of the feedstock.

Does method really change elution order with gc? It’s not like you have a binary or ternary mobile phase, it’s just mobile versus stationary phase interactions and the ramp of the oven. I thought it all boils down to (pun intended) volatility.

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Column used can change order. Temp/pressure profile shouldn’t. Different carrier gas (He/H2) might

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This is very cool, well done thus far. Any updates?

Did you try different carrier gas?

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