Chromatography Forum

hydrofluoric acid can do damage to Silica material, but it should be concentration dependant in my thought. Is it Ok to use it at low concentration, e.g 0.002% (~1mM)?

HF is a horrendous poison, can´t think of any reason to take the risk of handling it for HPLC.

Thanks for your answer.
People use TFA and FA for HPLC separation, I just wonder if HF can do better for some specific compounds since its pka is between TFA and FA. It is very toxic, but it should be also concentration dependant, a concentration as low as 1 mM should be OK?

Problem is, that to get to 1mM you need to start with a horribly corrosive toxin. I would imagine that your lab would require a specific risk assessment on this, and unless your analyte is the cure for cancer I would be surprised if the potential gains outweight the real risks.

Peter

It's lipid-soluble so it passes through skin. It's horrendously corrosive, kills nerves, inhibits glycolysis, does nasty things with calcium in the body, and even at 0.002% you are way over exposure limits if you get some in a glove and don't notice. On the other hand, in view of its extreme toxicity, were it used more widely in hplc labs there would be considerably less competition in the jobs market.

Ok, I see. I have to give it up in my mind.
Many thanks ro all of you.

Yes that is right, it passes through the skin attaches itself to the bone where it can not be left. One of the profs in the Colorado U Chem. dept. was the "father of Teflon". One of his students got a tiny amount of HF on his hands, they had to scrape the bone underneath.

Fluoride ion reacts with silica substrate quickly.

Problem is, that to get to 1mM you need to start with a horribly corrosive toxin. I would imagine that your lab would require a specific risk assessment on this, and unless your analyte is the cure for cancer I would be surprised if the potential gains outweight the real risks.

Peter

Not, whithout reason HF is not used.
It is small problem...compared with other problem.Here, volatility acid and glass breakage. But this is not the point...
2Padle 1234 - You have insurance with a good dentist ?

Thanks, guys.

Many years ago I worked with full size cylinders of 99.9% anhydrous HF. The forced air fully enclosed suit was fairly snazzy, but no fun after 12 hours!!

I got a tiny drop on my finger (someone did not close lid tight) and it hurt quite a bit for weeks, but no visible damage.