Non-volatile and Volatile Buffer Systems
Non-volatile buffers for anion exchange chromatography
pH interval | Substance | Conc. (mM) | Counter-ion | pKa (25 °C)1 | d(pKa)/ dT (°C) |
---|---|---|---|---|---|
4.3–5.3 | N-Methylpiperazine | 20 | Cl- | 4.75 | -0.015 |
4.8–5.8 | Piperazine | 20 | Cl- or HCOO- | 5.33 | -0.015 |
5.5–6.5 | L-Histidine | 20 | Cl- | 6.04 | |
6.0–7.0 | bis-Tris | 20 | Cl- | 6.48 | -0.017 |
6.2–7.2; 8.6–9.6 | bis-Tris propane | 20 | Cl- | 6.65; 9.10 | |
7.3–8.3 | Triethanolamine | 20 | Cl- or CH3COO- | 7.76 | -0.020 |
7.6–8.6 | Tris | 20 | Cl- | 8.07 | -0.028 |
8.0–9.0 | N-Methyldiethanolamine | 20 | SO42- | 8.52 | -0.028 |
8.0–9.0 | N-Methyldiethanolamine | 50 | Cl- or CH3COO- | 8.52 | -0.028 |
8.4–9.4 | Diethanolamine | 20 at pH 8.4 50 at pH 8.8 | Cl- | 8.88 | -0.025 |
8.4–9.4 | Propane 1,3-Diamino | 20 | Cl- | 8.88 - | 0.031 |
9.0–10.0 | Ethanolamine | 20 | Cl- | 9.50 | -0.029 |
9.2–10.2 | Piperazine | 20 | Cl- | 9.73 | -0.026 |
10.0–11.0 | Propane 1,3-Diamino | 20 | Cl- | 10.55 | -0.026 |
10.6–11.6 | Piperidine | 20 | Cl- | 11.12 | -0.031 |
Non-volatile buffers for cation exchange chromatography
pH interval | Substance | Conc. (mM) | Counter-ion | pKa (25 °C)1 | d(pKa)/ dT (°C) |
---|---|---|---|---|---|
1.4–2.4 | Maleic acid | 20 | Na+ | 1.92 | |
2.6–3.6 | Methyl malonic acid | 20 | Na+ or Li+ | 3.07 | |
2.6–3.6 | Citric acid | 20 | Na+ | 3.13 | -0.0024 |
3.3–4.3 | Lactic acid | 50 | Na+ | 3.86 | |
3.3–4.3 | Formic acid | 50 | Na+ or Li+ | 3.75 | +0.0002 |
3.7–4.7; 5.1–6.1 | Succinic acid | 50 | Na+ | 4.21; 5.64 | -0.0018 |
4.3–5.3 | Acetic acid | 50 | Na+ or Li+ | 4.75 | +0.0002 |
5.2–6.2 | Methyl malonic acid | 50 | Na+ or Li+ | 5.76 | |
5.6–6.6 | MES | 50 | Na+ or Li+ | 6.27 | -0.0110 |
6.7–7.7 | Phosphate | 50 | Na+ | 7.20 | -0.0028 |
7.0–8.0 | HEPES | 50 | Na+ or Li+ | 7.56 | -0.0140 |
7.8–8.8 | BICINE | 50 | Na+ | 8.33 | -0.0180 |
Volatile buffer systems | |||
---|---|---|---|
pH rang | Buffer system | Counter-ion | pKa-values for buffering ions1 |
3.3–4.3 | Formic acid | H+ | 3.75 |
3.3–4.3; 4.8–5.8 | Pyridine/formic acid | HCOO- | 3.75; 5.25 |
3.3–4.3; 9.3–10.3 | Trimethylamine/formic acid | HCOO- | 4.75; 9.81 |
4.3–5.8 | Pyridine/acetic acid | CH3COO- | 4.75; 5.25 |
4.3–5.3; 9.3–10.3 | Trimethylamine/acetic acid | CH3COO- | 4.75; 9.81 |
3.3–4.3; 8.8–9.8 | Ammonia/formic acid | HCOO- | 3.75; 9.25 |
4.3–5.3; 8.8–9.8 | Ammonia/acetic acid | CH3COO- | 4.75; 9.25 |
5.9–6.9; 9.3–10.3 | Trimethylamine/carbonate | CO32- | 6.35; 9.81 |
5.9–6.9; 8.8–9.8 | Ammonium bicarbonate | HCO3- | 6.35; 9.25 |
5.9–6.9; 8.8–9.8 | Ammonium carbonate/ammonia | CO32- | 6.35; 9.25 |
5.9–6.9; 8.8–9.8 | Ammonium carbonate | CO32- | 6.35; 9.25 |
4.3–5.3: 7.2–8.2 | N-ethylmorpholine/acetate | HCOO- | 4.75; 7.72 |
Materials
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