Dear Judy,
You are not alone. I am seeing pretty much the same thing with
column S/N 1640 Lot# 03H0-56082. It looked good at the beginning of its
life, but after about 380 gradients the column was giving pretty decent
separation of PTH-amino acids in the first half of the gradient, but the
resolution in the second half of the gradient was terrible (a metaphor for
middle age, perhaps?). I suspected there was something wrong with my pumps
or maybe the mobile phase.
Ever-helpful Bob is sending a replacement column, and I'm hopeful
that will clear up the problem.
Carol
At 09:59 AM 1/4/01 -0500, you wrote:
>Hello
>I am having a lot of difficulty with the Brownlee Spheri-5 PTH, 5 u, 220x2.1 mm
>columns that we purchase from ABI for the protein sequencer.
>
>The front half of the chromatogram is OK (separation and such) but the DTT is
>high. The back half, Pro and further, is not good. The peaks are too small.
>Proline is very large and tech support thinks that DPU is coming out too early
>and coeluting with Pro. The PMTC peaks are also way small.
>I am running Buffers A3 and B2. All reagents are fresh. New standards were
>prepared
>I tried putting back on my old column and these problems went away.
>Unfortunately the column is too old to use now.
>I have tried two new columns from ABI with the same result.
>
>Any clues?
>
>Thanks
>
>Judy Phelps
>phelp001@mc.duke.edu
>
>
>
Carol Manley Beach, Ph.D.
Protein Sequence Analysis
Macromolecular Structure Analysis Facility
232 Combs Cancer Research Building
University of Kentucky
Lexington, KY 40536-0096
cmbeach@pop.uky.edu
NOTE NEW AREA CODE: Mandatory after Oct 1, 2000
(859)257-4932 (office)
(859)257-4475 (lab)
(859)323-3909 (FAX)
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