>>> "Clogston, Chris" <cclogsto@amgen.com> 01/05 6:30 PM >>>
I recall a similar problem from when I used to run the old 470A sequencers.
It could be R4 dripping into the conversion flask (the valve block is
failing) during the reconstitution with S4. This usually manifested as an
intermediate problem that eventually showed up in every injection. Even a
tiny amount of TFA in the injection will create a huge peak early in the
chromatogram.
Chris Clogston
cclogsto@amgen.com
Amgen, Inc.
Thousand Oaks, CA 91320-1789
> ----------
> From: Bryan Smith[SMTP:bsmith@celltech.co.uk]
> Sent: Tuesday, January 05, 1999 12:38 AM
> To: Recipients of ABRF List
> Subject: Big peaks in pth chromatogram
>
> Manfred,
> I have been away for Christmas and have only just read your message, and
> Deb McMillen's reply. Maybe it is coincidence, but I had similar problems
> during December - large peak around the position of pth-N, somtimes big
> enough to obliterate half the chromatogram, but not on every run. This is
> on an old (very) 470A-190A, and suspecting contamination/other problem of
> lines etc, I have replaced the easier ones, plus column, reagents, etc.
> The problem seems less bad, but I still get an occasional peak of unknown,
> but at the pth-M position. I do not think that this is an air bubble
> problem as suggested by Deb McMillen - the odd peaks do not rise and fall
> that rapidly, they look like real peaks.
>
> Is it just coincidence that we both suffer this sort of problem at the
> same time? Is everyone else okay out there in sequencerland?
>
> Bryan Smith
> Celltech Therapeutics Ltd
> 216 Bath Road
> Slough
> Berks SL1 4EN
> UK
>
> -----Original Message-----
> From: Manfred Raida [SMTP:mraida@gmx.net]
> Sent: 21 December 1998 02:29
> To: Recipients of ABRF List
> Subject: big peak in pth-chromatogram
>
> Hallo to all,
> since a few days I have a strange problem with the separation of
> pth-amino
> acids on my 494 Procise. In several of the chormoatograms a big peak
> starting directly after N and going up to the upper detection limit
> occurs. The
> peaks goes up very fast and then "elutes" over the whole
> chromatogram. We
> checked the pumps, the chemicals, column, detector, performance,
> whatever may be
> the reason. It is not every chromatogram, sometimes 10 are without
> problem,
> sometimes on 2-3. There is no rule when it happens, the amino acids
> (if
> there is enough) are on this montain and can be detetcted clearly,
> but for
> sensitive analysis it does not work at all. It occurs in the
> standard and in the
> cycles.
> I am very thankful for any idea.
> Yours
> Manfred
> *************************************************
> Manfred Raida
> Niedersaechsisches Institut fuer Peptid-Forschung
> (IPF)
> Dep. of Analytical Peptide-Chemistry
> Feodor-Lynen Strasse 31
> D-30625 Hannover
> Germany
> E-Mail Manfred_Raida@compuserve.com
> Tel.: +49 511 5466 210
> Fax: +49 511 5466 102
> **************************************************
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