Steve,
I have been using Solvent A lot # 36-08052TU and have not seen the lumps
you describe on either of my two sequencers. The baseline rise with this
lot is about 1.5 mAu which is about twice what I used to get. These days
I'm just thankful when the will actually ship it to me. Last time I waited
more than 30 day to get my Solvent A.
I would be interested in seeing your formulation for Solvent A. I have
taken to formulating many of the HP reagents such as S2/3, S3, S2A (OK, S2A
you just pour from the bottle) either because of quality or supply
problems. It looks like L3 will soon fall into that category too. With the
down turn in the quality of support for our sequencers I think it is best
to be as independent of HP/Agilent as possible.
I think the original formulation of Solvent A was NaHPO4, buffer with
hexanesulfonic acid as ion pairing agent with MeCN. Is there a particular
reason you went with your formulation?
For acetic acid, have you tried EM Science OmniTrace (AX0077-1). I use that
for the HPLC buffers I use with mass spec and it seems to be fairly clean.
--tks
Tim Slattery
Berlex Biosciences
Protein Biochemistry and Biophysics Department
StvTindall@aol.com on 02/02/2000 10:44:16 AM
To: Recipients of ABRF List <abrf@aecom.yu.edu>
cc: Bill_Gette@agilent.com (bcc: Tim Slattery/RM/USR/SHG)
Subject: Potentially Defective HP G2000A (PTH-A Buffer)?
Fellow HPers (or is it ATers?):
HP G2000A (Solvent A) Lot # 36-00855TU is giving rise to a broad
"hump"
in the N-S-T-Q-G region and several "lumps" in the DPTU-W-K-F-I-L region.
The heights of the later "lumps" are in the 2-5 "pmol" range, which makes
the
buffer unusable for low pmol signals. This phenomenon has been seen
in-house
with two different bottles of G2000A from the same lot and on two HP
sequencers. If the description of the problem is not clear, I can send you
some chromatograms (PDF).
If you are having this problem and are out of usable buffer, drop me a
note and I can send you a prototype formulation for a substitute buffer
which
closely mimics the G2000A. The prototype is based on using sodium
heptanesulfonate, HOAc, TEA and MeCN and is NOT trivial to make (Does
anyone
know of a HPLC-grade HOAc?). If properly adjusted for ion-pair
concentration
and pH, the elution positions of the standard residues are virtually
identical to those obtained with G2000A (PDF chromatogram available). The
elution positions of the nonstandard residues using this substitute have
not
been characterized.
Steve
====================
Stephen Tindall, Ph.D.
Argo BioAnalytica, Inc.
====================
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