For several weeks, our 3.5 chemistry has been plagued by a broad peak
integrating as 2-10 pmol Gln in cycle-1, which usually decreases in intensity
as the runs progress. The 3.5 RY and IY are fine, but the artifact reeks
havoc with integration. The artifact is not present when using 3.1 chemistry.
We reported a similar/identical artifact about this time last year and several
groups indicated that they were experiencing the same problem.
We are also occasionally seeing a second artifact peak eluting just after
Lys, which can usually be avoided by resetting the Lys integration retention
time. It is not clear whether the "Gln" and "Lys" artifacts are related to
the same problem.
Based on observations after switching reagents between sequencers, this
year's "Gln" problem seems to be strongly linked to R2 lot# 28-AMLX-BC and may
be weakly linked to S2/3 lot# 31-3197-19. When both are replaced, the "Gln"
problem goes away.
Would anyone having the same "Gln" artifact problem under 3.5 chemistry
please post the R2 and S2/3 lot numbers that you are currently using?
Thanks in advance for your input,
Steve
P.S. By the way, who thought up this stupid letters-as-lot-numbers idea,
anyway? They are harder to key in correctly and the "0"'s and "O"'s look the
same. I'll bet that cGMP labs are having a fit with this one.
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Stephen Tindall
Argo BioAnalytica, Inc.
Phone: 1-973-605-2100
Fax: 1-973-605-2104
StvTindall@aol.com
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