Bio-Rad ENrich™ High-Resolution Ion Exchange Columns User Manual
Page 8
4 ENrich Instruction Manual
Table 2. Buffers for ion exchange chromatography.
Anion Exchange — ENrich Q
pH
Range
Buffer
MW
pKa @
25°C
Counter-Ion
pKa/°C
5.0–6.0
Piperazine
86.1
5.7
Cl-/HCOO
–
–0.015
5.0–6.0
L-histidine
155.2
6.15
CI
–
–
5.8–7.2
Bis-Tris
209.2
6.5
CI
–
–0.017
6.4–7.3
Bis-Tris propane
282.3
6.8,9
CI
–
–
7.3–8.3
Triethanolamine
149.2
7.8
CI-/CH3COO
–
–0.02
7.6–8.6
Tris
121.1
8.1
CI
–
–0.031
8.4–8.8
Diethanolamine
105.1
8.9
CI
–
–0.025
9.0–9.9
Ethanolamine
61.1
9.5
CI
–
–0.029
9.8–10.3 1,3-diamino-
propane
74.1
10.5
CI
–
–0.023
Cation Exchange — ENrich S
pH
Range
Buffer
MW
pKa @
25°C
Counter-Ion
pKa/°C
3.6–4.3
Lactic acid
90.1
3.8
Na
+
–
4.2–5.2
Citric acid
192.1
3.1
Na
+
–
5.5–6.7
MES
195.2
6.1
Na
+
–0.011
6.1–7.5
PIPES
302.4
6.8
Na
+
–0.009
6.5–7.9
MOPS
209.3
7.2
Na
+
–0.006
6.7–7.6
Phosphate
120/142
7.2
Na
+
–0.003
6.8–8.2
TES
229.2
7.4
Na
+
–0.002
6.8–8.2
HEPS
238.3
7.5
Na
+
–0.014
7.4–8.8
Tricine
179.2
8.1
Na
+
–0.021
Always use buffer components of the highest purity available,
as UV-absorbing impurities may cause baseline disturbances
and interfere with the detection of protein peaks. Always filter
and degas buffers.