We've begun to use them to desalt and concentrate peptide digests before
MALDI. The results are impressive -- sensitivity shot up markedly. They
are easy to use, and fast. But they're meant to be used with a 10 ul
pipette, so if the sample is over 10 ul, you have to process it in
portions. It probably does take only a minute to handle a sample of 10 ul
or less, but the time will increase with larger volumes. And it's one
sample at a time; this is no 96-well proposition.
One trick suggested by Millipore for samples destined for MALDI is to elute
with matrix in acetonitrile, instead of eluting with acetonitrile (50%),
then mixing with matrix. This works well in my limited experience, being
convenient and giving the expected increase in sensitivity due to a more
concentrated sample. I just spot the sample directly on the target with
the ZipTip.
We haven't yet evaluated them for desalting after alkylation in guanidine
with IAA, but we plan to do so. I would guess that they will work quite
well, provided that the protein recovery is reasonable. (It was excellent
with our peptides.)
Rod Levine
NIH
Bldg 3, Room 106 MSC 0320
Bethesda, MD 20892-0320
email: rlevine@nih.gov
voice: 1 (301) 496-2310
fax: 1 (301) 496-0599