Last year we used a microdrop pipetor that can pipet nanoliter amounts of a premixed solution of peptide and matrix. The spots that were made were very small. Using a Kratos MALDI 4 without delayed extraction, we were able to see as little as 3 pmoles deposited, it was a mediocre spectrum, but we got good spectra and around 200 resolution for the 10 atomoles deposited. I think that the secret of success is in making small sample spots.
Amina
Amina S. Woods, Ph.D.
Johns Hopkins School of Medicine
725 N Wolfe St., Baltimore, MD 21205
Tel: (410) 614-4981, Fax: (410) 955-3420
E-mail: amina@welchlink.welch.jhu.edu
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From: Kenneth Williams [SMTP:Kenneth.Williams@yale.edu]
Sent: Thursday, January 22, 1998 4:00 PM
To: Recipients of ABRF List
Subject: High Sensitivity Protein Identification
I'm looking for references/unpublished observations for extremely high
sensitivity MS or MS/MS protein identification - at or below the low amol
level - to help one of our users who would like to propose (in a grant
application) identifying some proteins at very low levels. My guess is
MALDI/peptide mass searching is the most sensitive approach but perhaps I
am wrong. Any help would be appreciated.
Thanks very much,
Ken Williams
Yale/Keck Labs