-----Original Message-----
From: Dirk S. Krapf [mailto:dkrapf@gilson.com]
Sent: Thursday, March 04, 1999 10:33 PM
To: Recipients of ABRF List
Cc: Xuguang Yan
Subject: Protein mass of+n57 Da (n=1,2,3....9)
>Date: Thu, 4 Mar 1999 11:07:56 -0800 (PST)
>From: Xuguang Yan <yanx@ucs.orst.edu>
>To: krapf@abrf.org
>Subject: Protein mass of+n57 Da (n=1,2,3....9)
>
>
>Good morning all! I have a question for the MS guru's.
My reduced protein
>with a mass of 24523. When I run it with LC-ESI-MS(
Vydac C4 150X0.3mm
>column, 0.06%TFA/Water as bottle A, 0.05%TFA/ACN as
bottle B, 30%B to 80B%
>in 30min as the gradient), in addition to the desired
mass, I always found
>a series mass with nX57Da (n=1,2,3...9) bigger, I doubt
they come from TFA
>(TFA MW=114), but I don't know how to avoid it.
Actually I also tried
>0.1%HCL/Water and0.1%HCL/ACN as my elution phase, and
it gives me another
>series mass of nX36Da(n=1,2)bigger and sometime n57
Da(n=1,2) bigger mass
>also appeared. With this system, I never have this
problem when I run
>peptides. And I don't think it comes from the impurity.
Could someone tell
>me how to prevent this unexpected series masses and how
it comes from? I
>would be most grateful!
>
>Xuguang Yan
>OSU
>yanx@ucs.orts.edu
>
>
>