[Hachiko]

Dear all,
My compound is low soluble so I need much polar solvent to dissolve it, when I runned column, I got the mixing. I think the reason is that my solution had low concentration and polar solvent make my sample all run together. I can't use dry loading because my compound can be soluble in solvent system. I try recrystallization but it's not good.
Could you share your opinion and experience when you handle with low solubility compound in column chromatography?

[phth]

Change the stationary phase, i.e. maybe alumina will work over silica gel or C18 or ion-exchange. You could try more recrystallization solvents; get some small test tubes and a hot bath. Test more and TLC solvent systems. If your compounds are not crystallizing/forming a gel at room temperature then lower the temperature.

[Hachiko]

Change the stationary phase, i.e. maybe alumina will work over silica gel or C18 or ion-exchange. You could try more recrystallization solvents; get some small test tubes and a hot bath. Test more and TLC solvent systems. If your compounds are not crystallizing/forming a gel at room temperature then lower the temperature.

Thank you for your suggestion.I will try different solvents for recryatallization.

[Babcock_Hall]

We have also experienced similar problems.  Can you tell us what your solvent system is and what solvent you are using to dissolve the solute?

[kriggy]

I dont understand, why you cant use dry loading?

[Hachiko]

We have also experienced similar problems.  Can you tell us what your solvent system is and what solvent you are using to dissolve the solute?

I use DCM for dissolve and 4Hexane:1Ethyl acetate for mobile phase.

[Hachiko]

I dont understand, why you cant use dry loading?

Oh,I may see my mistake here. I check the solvent system that I will use for mobile phase to dissolve my sample. My sample can be dissolved in this solvent system so I think dry loading is not good. So if I use dry loading and firstly run with hexane and increase the polarity slowly, will it be ok?

[kriggy]

Yeah thats pretty much what I do all the time. I dissolve the sample in DCM, add silica, evaporate to dryness, add to collumn and use hexane:EtOAc as a mobile phase. TBH I dont even bother trying to dissolve my samples in mobile phases I use

[Hachiko]

Yeah thats pretty much what I do all the time. I dissolve the sample in DCM, add silica, evaporate to dryness, add to collumn and use hexane:EtOAc as a mobile phase. TBH I dont even bother trying to dissolve my samples in mobile phases I use

thank you for sharing.