Chromatography Forum

Hi all,

I've been working on a separation for a compound that the company I work for have been recently developing. All that is required, for the moment, is a method that separates the starting material (9,9-dioctyl 2,7-dibromofluorene) from the product which is, obviously, a derivative of the starting material.

I was wondering if anyone has any advice for the chromatography of fluorene based compounds? The starting material, and indeed the product, do not have high solubilities in some of the more polar solvents and some trial runs have yielded poor peaks and lousy responses for 0.1mg/mL solutions. Increasing this concentration is probably not possible due to solubility issues I have mentioned above.

Both compounds exhibit good solubility in THF and a reasonable separation has been achieved with this solvent and water but there are stability issues surrounding the product in THF. This is a concern as eventually the method will be needed for quantitative analysis.

Any advice would be much appreciated.

Kind regards,

James

I assume that everything you have looked at so far has been in reversed-phase mode. This may be a good candidate for "conventional" normal-phase chromatography using non-polar solvents with a polar bonded-phase column (or even a bare silica column, for that matter). It may be that the starting point should be "what *is* it soluble in?" (yes, poor grammar, but you get the point ).

Another thought: how bad is the stability in the presence of THF? With a state of the art column (short, small particles), the residence time on the column would only be a matter of a few minutes. The catch would be to find a compatible diluent for your sample that does not contain THF.

Hi Tom,

Apologies for not responding sooner.

The work I was doing was not part of a priority project at work and as such I can't imagine any sort of major expenditure will be afforded to this separation. I imagine the column you describe at the end is somewhat expensive?

The work has now been handed over to a different department due to higher priority work being assigned in the last week. I did consider normal phase chromatography given the nature of the compound. I have mentioned this to the lab that will be taking over the work.

Thank you again for your reply.

Regards,

James