Bio-Rad UNOsphere™ Rapid S Media User Manual
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Table 2. Common Buffers for Cation Exchange Chromatography.
Buffer Buffering
Range
Acetic acid
4.8–5.2
Citric acid
4.2–5.2
HEPES 6.8–8.2
Lactic acid
3.6–4.3
MES
5.5–6.7
MOPS 6.5–7.9
Phosphate
6.7–7.6
PIPES 6.1–7.5
TES 6.8–8.2
Tricine 7.8–8.9
Section 7
Regeneration
After each run, the packed bed should be washed with 2–4 bed volumes of
1–2 M NaCl to remove reversibly bound material. Samples may be loaded onto the
column after reequilibration in starting buffer.
Section 8
Cleaning-in-Place (CIP) and Sanitation
If a column no longer yields reproducible results, the media may require thorough
CIP and sanitation to remove strongly bound contaminants. Acceptable CIP agents
include 25% acetic acid, 8 M urea, 1% Triton X-100, 6 M potassium thiocyanate,
70% ethanol, 30% isopropyl alcohol, 1 N HCl, 1 N NaOH, and 6 M guanidine
hydrochloride.
1. Sanitize the support in the column with 2–4 bed volumes of 1.0 M NaOH at
50–100 cm/hr while maintaining a minimum contact time of 40 min.
2. To reequilibrate the column, wash the column with 2–4 bed volumes of
0.5–2 M NaCl solution (containing 50–100 mM buffer).
3. If lipid removal is required, the column may be washed with a 20–50% ethanol
solution at 50 cm/hr.
Section 9
Storage
For long-term storage, UNOsphere media should be equilibrated with 20% ethanol.
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