From: Jonas Nilsson (jonni$##$ifm.liu.se)
Date: Wed Oct 27 1999 - 03:46:35 EDT
Hello.
Just evaporate off the eluent!
Instead of a buffered system, you can use triethylamine (0.1%) or
trifluoroacetic acid (0.1%) in the eluent to control pH. If you need a buffer,
the only reasonable volatile buffer i know of is ammoniumacetate, which could be
lyophilized off after evaporation of the solvents (MeOH/Water; MeCN/Water or
whatever you use).
Why would there be a problem in evaporating off the water?
Bozell, Joe wrote:
> ORGLIST members:
>
> A seemingly simple question. Our group recently purchased our first LC, and
> we have been using reverse phase columns to do our analytical separations,
> such as routine reaction monitoring. We are now considering the purchase of
> a preparative column for the system to speed up actual product isolation on
> the gram scale. However, when we consider product isolation from the column
> fractions, it sounds like it could be messy. We're using MeCN/water
> mixtures for the analytical, and sometimes phosphate buffers. Is there a
> generic, generally applied technique to isolate your compound from these
> mixtures? It seems like the best approach would be to strip the organic,
> and then extract the compound from the aqueous residue into another solvent.
> However, this looks like an invitation to yield loss, since it's a lot more
> manipulation (strip, extract, separate, dry, strip again) than isolating
> ones compound from a straight phase column and just stripping the solvent.
> We really like reverse phase for analytical, and don't want to go back to
> straight phase to make the preparative scale separations easier, since we'd
> have to reoptimize all of our solvents and conditions.
>
> Is there any good folk art out there regarding a nice general procedure to
> deal with fractions from preparative reverse phase LC?
>
> thanks,
>
> Joe Bozell
> Senior Chemist
> National Renewable Energy Lab
> Golden, CO USA
> __________________
>
> ORGLIST - Organic Chemistry Mailing List
> Website and Archive: http://www.orglist.net/
> List coordinator: Joao Aires de Sousa (jas$##$mail.fct.unl.pt)
--
_____________________ _____________________
| Jonas Nilsson | | |
|Linkoping University | | Telephone |
| IFM | | --------- |
| Dept. of Chemistry | | work: +46-13-285690 |
| 581 83 Linkoping | | fax: +46-13-281399 |
| Sweden | | home: +46-13-130294 |
|_____________________| |_____________________|
__________________
ORGLIST - Organic Chemistry Mailing List
Website and Archive: http://www.orglist.net/
List coordinator: Joao Aires de Sousa (jas$##$mail.fct.unl.pt)
This archive was generated by hypermail 2.1.4 : Fri Sep 19 2003 - 12:15:04 EDT