Bio-Rad Macro-Prep 25 S Media - Manual (Page 8)

Buffer exchange can be accomplished using Bio-Spin ® 6 or Bio-Spin 30 columns,
Econo-Pac ® 10 DG desalting columns, Bio-Gel ® P-6 DG size exclusion gel, or the
Econo-Pac P6 cartridge. The choice of product depends on the sample
volume.
Table 2. Common Buffers for Ion Exchange Chromatography. 1, 2, 3
Type of Ion Exchanger Buffer Buffering Range
Macro-Prep 25 S Acetic acid 4.8–5.2
Citric acid 4.2–5.2
HEPES 7.6–8.2
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
Pivalic acid
4.7–5.4
TES 7.2–7.8
Tricine 7.8–8.9
Macro-Prep 25 Q Bicine 7.6–9.0
Bis-Tris 5.8–7.2
Diethanolamine 8.4–8.8
Diethylamine 9.5–11.5
L-histidine 5.5–6.0
Imidazole 6.6–7.1
Pyridine 4.9–5.6
Tricine 7.4–8.8
Triethanolamine 7.3–8.3
Tris 7.5–8.0
Buffer Preparation
When preparing buffers for ion exchange chromatography, it is important that
excess conductivity is not produced during buffer pH adjustment. For example,
back-titration of Tris-HCl with NaOH elevates conductivity, which will lower binding
capacity. To prepare Tris buffer, begin with Tris base and titrate with Tris-HCl to the
target pH. Apply the same principle with other buffers.
Column Equilibration
To equilibrate the column, wash with 1–2 CV of buffer containing 0.5–1.0 M of the
buffer salt used in the start buffer, then follow with 3 CV of the start buffer or until
pH and conductivity are stable.
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