And other than that, isn't it possible that the oligo could hang onto some
of the salts from the HPLC mobile phase and later in solution create what
you are seeing? Have you check the pH of the oligo after resuspension in
water?
Deb McMillen
Institute of Molecular Biology
University of Oregon
EUgene OR 97403
On Thu, 28 Oct 1999, Alain LAURENT wrote:
> Dear ABRF
>
> Thank you for all of them who answer to my questions and the few tricks they
> gave to me
>
> I understand sometimes it can be sequence dependent but we are working at
> very low concentration (40-200 microM) and it seems to me a bit strange that
> precipatation occurs . The clouds cannot be any silica since they appear
> after HPLC purification (Triethylammonium acetate buffer 0,05 M) and I use a
> polymeric phase pH insensitive . There is no ammonia loaded on the HPLC. The
> oligos are dried down with buffer (no further desalting since TEEA is
> volatile). If the dried residu is resuspended in water we often have some
> "clouds" if it is 2% NH3 solution it works fine. I was more encline to think
> it was something to do with water and the pH.
>
> Thank You
>
> Alain
>
>
>
> >I wonder if any of you could give me some advices regarding the solubility
> >of oligonucleotides after HPLC purification. It happens sometimes and even
> >for short oligos that a precipate appears after solubilization of dried
> >oligos in water. All of these oligos have been purified by HPLC. From my
> >point of view it cannot be any remains of silica. I wonder if it is related
> >to the water (we use MilliQ water) or to the sequence of the oligos. Most of
> >the time if we use › 2% NH3 solution to solubilize the oligos then it works
> >fine and no precipitate appears.
>
> >Any scientific suggestions ?????
>
> >Thank you very much
>
>
> >Alain
>