29
Protocol
1. Remove a 1 or 2 µl aliquot of
the reaction mixture to a
clean microcentrifuge tube
containing 20 µl of water
or 10 mM Tris/HCl pH.8.0.
1 mM EDTA buffer. Mix well
by pipetting up and down.
2. Spot, in quadruplicate,
5 µl aliquots of this dilution
on to Whatman DE81
chromatography paper
squares (minimum size
1 x 1 cm), placed on a non-
absorbent backing. These
squares may be marked
with a pencil for identification
if required.
3. Take two of the filters and
dry under a heat lamp.
10–15 minutes should be
adequate.
4. Wash the remaining two
filters twice for 5 minutes
each, at room temperature
in excess 2xSSC (30 mM Na3
citrate, 300 mM NaCl pH7.0)
using gentle agitation. Rinse
briefly in distilled water and
then once with ethanol for
5 minutes. Then dry the
filters under a heat lamp.
Notes
4. In aqueous solution DE81
paper becomes fragile and
care should be taken when
handling. In order to stabilize
the paper the squares are
rinsed in ethanol.