Bio-Rad AG® MP-50 Cation Exchange Resins - Manual (Page 5)

Adjust pH to 8.0 with 8-10 ml concentrated HCl.
Add distilled water to 4.0 liters.
500 ml beaker
Test tube rack for Poly-Prep
® chromatography
columns
Test tubes or other containers to collect DNA
4.2 Protocol
1. Use about 1.5 ml (approximately 1.1 grams) of
Molecular Biology Grade AG 50W-X8 resin in a
column for each gradient tube. The resin may also be
autoclaved in the Poly-Prep chromatography
columns, if a sterile preparation is desired.
2. Slurry the resin for each column to be poured in 2.3
volumes of A-50 buffer. Pour all at once into a Poly-
Prep column. Do not snap the tip off the column until
ready to proceed with Step 3. At this time, the resin
and column may be autoclaved.
3. Snap the tip off the column and wash the column
with 20 ml of A-50 buffer.
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the resin. Figure 1 shows the removal of (A) ethidium
bromide and (B) propidium iodide by Molecular Biology
Grade AG 50W-X8 cation exchange resin. R is the resin
matrix; SO
3
- is the functional group covalently attached
to the resin.
Section 4
Sample Protocol
The following procedure was developed by
Rodriquez and Tait to remove propidium iodide from
intact plasmids, and is used for DNA concentrated on
cesium chloride gradients.
1
4.1 Material required
Concentrated HCl
A-50 buffer (4 liters):
Trizma base 24 grams (50 mM)
NaCl 117 grams (500 mM)
0.25 M EDTA 16 ml (1 mM)
1 M NaN3 4 ml
Distilled water 3.5 liters
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