Chromatography Forum

I got HPLC fraction. Fraction is H2O/ACN/Formic acid=90/10/0.1 and cotain my target compound.
How to neutralized this solution?
I chage pH 3, 4, 5, 7 by NaOH solution. and extract by Butanol. But my compound didn't trasfer to
Butanol layer.
I want to transfer my compound to organic layer and evaporlate to check NMR.
But my compound is always water layer so if I evaporate water layer, Formic acid concetrate is high
so NMR signal is only Formic acid.

I'm assuming your compound is a base. If it is, you need to get the pH above the pKa in order to extract into the organic (and even then there is no guarantee, if the rest of the molecule is hydrophilic!). Try going up to pH 9 or even 11 and see what happens.

A thought for a different approach: If your compund is basic, you may want to try to put it on an SPE cartridge and then elute it in a solvent (like methanol or acetonitrile with out any water present) that evaorates more easily. You may be able to make use of acid/base characteristics to retain and elute your compund.