Have you considered an amino acid analysis of a weighed sample and
including an internal standard? Knowing the amount of peptide present
could by difference yield the amount of water and salts.
-Lowell Ericsson, Dept. of Biochemistry, U. of Washington, Seattle, WA
On Fri, 21 Jan 2000, Breslav, Michael [PRI] wrote:
> Joseph,
> 1. There is Karl Fisher titration for H2O and ion-chromatography for
> counter-ions. Any contract analytical lab will do it.
> 2. Esters are not stable to HF cleavage. However I can imagine that
> theoretically you can cleave some of the acid labile groups without ester
> cleavage using low HF cleavage for a short time.
> Michael Breslav
> R.W.Johnson PRI
> Spring House, PA
>
> > -----Original Message-----
> > From: Fuselier de la Claire [SMTP:devildog@mailhost.tcs.tulane.edu]
> > Sent: Thursday, January 20, 2000 6:59 PM
> > To: Recipients of ABRF List
> > Subject: Pepsyn: A couple of questions
> >
> > What is the best way to quantitate the amount of H2O and counter-ion in
> > a sample of lyophilized peptide?
> >
> > Are esters stable to HF cleavage?
> >
> > --
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Joseph A. Fuselier
> > Peptide Research, SL12
> > Tulane University School of Medicine
> > 1430 Tulane Avenue
> > New Orleans, Louisiana 70112 USA
> > 504.588.2296
> > (fx) 504.584.3586
> > devildog@mailhost.tcs.tulane.edu
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
>
>
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