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
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Stephen Tindall, Ph.D.
Argo BioAnalytica, Inc.
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