Chromatography Forum

Happy holidays everyone.

I was going to wait until January to post this, but I'm happy to see there are a few people at work this week (like me).

We are doing a normal phase separation. Mobile phase is pure hexane (and we do a washout at the end of the run with ethyl acetate). We have tried both diol and cyano columns. We are seeing some tailing of one peak (Quercetin). It is a peak that is known to tail considerably during reversed phase: a problem which can be easily addressed by using acid and/or a polar embedded column.

But I must confess I've never seen this kind of problem with normal phase. Is there any additive or acid that we can add that is soluble in hexane; and that might eliminate the tailing?

Any suggestions how to solve the problem would be very much appreciated.

Much Thanks!

I'd suggest a little( 0.05 - 0.5% ) acetic acid, perhaps with a few % of ethanol - if there are problems of phase separation due to water on the silica.

I would also perform a quick Internet search for the systems used for TLC separation, that should give more suggestions.

Please keep having fun,

Bruce Hamilton

One of my colleagues thought that adding a small percentage of an amine might help. It would have to be a long chain amine, so that it would be soluble in hexane.

Any one ever tried this?

Thanks!