Chromatography Forum

Dear all,

I have two substances, that are very similar: Estriol and 9,11-Didehydroestriol (see picture).

What type/method (RP-mode only) would you recommend for the separation of these two substances?

Thank you very much for any hint.

Regards

Florian

Not exactly what you asked, but personally I'd try capillary GC after trimethylsilyl derivatization.

The extra hydrogen on 9 is obviously a typo.

If those are the only two compounds to be separated, then a phenyl column might give a bit better selectivity than a C18 for the presence/absence of that double bond. If there are other compounds in the sample as well, then it's a toss-up.

Hi,
separating Estriol and 9,11-Didehydroestriol by HPLC isn't very complicated. Most C18-Columns (150mm, 3µm) will do. Some will also separate 9,11-Didehydroestriol and 6-Didehydroestriol.

Alex

Hello,¨

DawnRazor: you are right: the H-atom at position 9 is wrong as noticed by Tom Jupille.

Alex: your statement sounds as you might be experienced in this kind of separation. Do you have an application or similar?

Thank you very much to all responders.

Regards

Florian

Kinetex PFP! I just was at the presentation for Kinetex columns.

I would try two possibilities
both from cosmosil for exactly those types of molecules

I would start by the Cholester type. I know of an application for vitamin D2 and D3 where the column helps splendid and the separation is super simple with MeOH Water

another possibility is Pi-NAP to try and do separation on the pi-pi in the molecules but this column uses naphtylethyl group which gives better solution then a phenyl column

the advantages of these columns in these applications is the use of simpler mobile phases with less modifiers

A related separation can be found in the 2nd chromatogram in the following link: http://www.dionex.com/en-us/products/co ... 87227.html. The column is Acclaim Phenyl-1, 3-um column.

Florian,

I don't have a recent method on Estriol. If I had, it would be IP of my employer anyway. I would go with a C18 or C8 and try methanol and ACN as organic additives. Small pore size materials can have advantages.

Alex