David T. Chin
Director, Protein Core Facility
Protein Chemistry and Expression
2-17 Agriculture Building
Univ. of Missouri - Columbia
Columbia, MO 65211
SHIPPING AND ACTUAL LOCATION:
2-17 Agriculture Building (office)
2-31 Agriculture Building (Lab)
e-Mail: chind@missouri.edu
web: http://www.biotech.missouri.edu/pc
[mailto:chind@missouri.edu]
Phone: 573-882-2027
Fax: 573-882-7105
-----Original Message-----
From: Deb McMillen [mailto:mcmillen@morel.uoregon.edu]
Sent: Friday, April 23, 1999 5:28 PM
To: Recipients of ABRF List
Cc: abrf@aecom.yu.edu
Subject: Re: Mystery peaks from HS Procise 494
Ken, Maybe you should list the lot numbers on the reagents that were
changed just before this happened--this might help see if others got new
peaks from the same lot numbers--or if it was just coincidental that the
problem arose after changing reagents. And just a thought, I know on
my RP columns using TFA/Accn gradients, that old TFA will give peaks that
have some retention on columns, but do elute fairly early--I
wonder if TFA is one of the reagents that was changed.
Deb McMillen
Institute of Molecular Biology
University of Oregon
Eugene OR 97403
On Fri, 23 Apr 1999, Kenneth Williams wrote:
> A triplet of peaks has suddenly appeared on the HPLC chromatogram from our
> HS Procise 494 that we cannot seem to rectify - any help/ideas would be
> greatly appreciated. Here are the clues to this puzzle:
>
> 1. the first two peaks co-elute with Pth-Gly and Pth-Glu with the third
> eluting between Pth-His and Pth-Ala. By comparison to the standards the
> relative "pmol" amounts of these peaks are about 0.5 pmol (Gly), 2 pmol
> (Glu) and 1 pmol (X).
>
> 2. these peaks appeared following addition of several new reagents to the
> instrument - all of which have subsequently been changed again.
>
> 3. the peaks are present at the same level in all cycles and the
instrument
> is still sequencing normally.
>
> 4. the peaks are present also in the blank cycle.
>
> 5. the flask has been KOH washed and the column guard has been changed
> without effect
>
> 6. the Pth column is 4 weeks old while this problem occurred suddenly a
few
> days ago
>
> Currently, our efforts are directed towards watching a blank cycle to be
> sure all wash steps are indeed occurring and then, to deleting steps from
> the wash cycle program until we isolate the step or reagent causing these
> peaks.
>
> If you have seen these peaks previously and/or have any ideas on their
> origin or how to more effectively diagnose the problem please respond.
>
> Thanks very much,
> Ken Williams
>