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Why are MeOH and ACN the most used organic solvents in HPLC?

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

7 posts Page 1 of 1
Thank you all for your time.

I'm battling with this question.

There is many information about whats different about them, but not why they are the most used.

Many say there are the most used because there is so much already published with them, but this don't say anything about why they started to be so much used in the first place.

Not really easy to understand why, from all the organic solvents known, this two get to be so popular in HPLC.

Thanks for all your help and have a nice day.
I'll weigh in. You can get them in pretty pure form. They are infinitely soluble in water. They can support fairly large salt concentrations as well - especially when combined with water. This combination of physical characteristics gives you a lot of flexibility to alter the mobile phase to suit your needs. Others?
ACN has a low viscosity, neither form peroxides and of course they don't absorb UV beyond about 210nm.
About a dozen years ago I was surprised to find that there was an "HPLC grade" acetone offered. It wouldn't be much good for UV work.
UV-Cutoff is a biggie. MeOH has a slightly higher cut-off, with ACN being able to go as low as the detectors.

A more interesting question would be the MeOH Vs. ACN debate.
Thank you everyone. You were a big help.


Just in case anyone else battle with this, here are some data previews replies mention:

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Good work and good luck!
As Stive Reimer point out, ACN and Methanol too have low viscosity which means lower backpressure and not least faster mass transfer. The former means possibility to utilize smaller particles for instance. While the latter means higher plate counts.
Favorable UV cut off, miscibility with water, purity and all other factors mentioned here are true as well.

Best Regards
Learn Innovate and Share

Dancho Dikov
ACN has a low viscosity, neither form peroxides and of course they don't absorb UV beyond about 210nm.
About a dozen years ago I was surprised to find that there was an "HPLC grade" acetone offered. It wouldn't be much good for UV work.
Hello All!

I agree with Steve but acetone has "saved my life" many times as solvent, for example anaysing vitamin d3 disolved in corn oil I added a few ml of acetone and fill to the mark with mobile phase. The big peak of acetone comes first not interfering at all.

Best regards

Fernando
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