Re: Digest: PEG
POLYLC@AOL.com
Mon, 29 Jun 1998 22:27:08 EDT
A good general protocol for getting nonionic detergents out of samples is to
use Hydrophilic Interaction Chromatography (HILIC). This was discussed in the
Dec. '97 issue of ABRF News; see also Jeno et al., Anal. Biochem. 215 (1993)
292. To get the detergents out of a digest on a small scale, add 5 volumes of
acetonitrile to the sample and apply it to a small column of a very polar
material. An example is the ultramicro spin cartridges of Amika packed with
PolyHYDROXYETHYL A; these can run as little as 5 ul of sample. The cartridges
fit into a microcentrifuge tube and sequential washes are performed in a
microcentrifuge. Detergents aren't retained and pass right through the
cartridge, while virtually all peptides are retained. You can then elute the
peptides with a step to water. The cartridges can be reequilibrated with 85
or 90% acetonitrile and reused.
Andy Alpert
PolyLC Inc.
Columbia, MD USA