Derek,
I have seen this problem too. My best guess a the reason for the loss is
adsorption of the peptides to the container walls. I have a few
suggestions.
-Add a sacrificial peptide. A clean peptide added at 0.5 -1.0 pmol could
bind to the container and still leave your peptides in solution.
-Store at -80, Many times my solutions will not freeze in at -20.
-Store the peptides on a solid phase. adsorb them to a ziptip and keep it
in the freezer. I have seen this mentioned in the literature before.
Hope this helps. Happy Holidays
Mike Knierman
Derek Bradley <Derek.Bradley@ucl.ac.uk>
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Subject: MS: Tryptic Digest Stability
Hi Guys,
Does anyone out there know how stable tryptic digest solutions are? I'm
generally only able to do nanospray MS/MS analysis on samples after
they're
at least 2-3 days old and often older (stored at -20C) and tend to find
great difficulty in getting any meaningful results from them. I realise
that
immediate analysis would be preferable but this isn't always possible so
what is the best way of storing them ? Currently due to processing methods
they are stored in 10% formic acid solution at -20C.
Does anyone have any ideas?
Cheers,
Derek Bradley
Dept. of Medicine
UCL
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