| pKa Value and Buffer Range of important Biological Buffers sorted alphabetically |
| |
| buffer |
pKa 25°C |
effective pH range |
| |
| ACES |
6.78 |
6.1-7.5 |
| acetate |
4.76 |
3.6-5.6 |
| ADA |
6.59 |
6.0-7.2 |
| ammonium hydroxide |
9.25 |
8.8-9.9 |
| AMP (2-amino-2-methyl-1-propanol) |
9.69 |
8.7-10.4 |
| AMPD (2-amino-2-methyl-1,3-propanediol) |
8.8 |
7.8-9.7 |
| AMPSO |
9 |
8.3-9.7 |
| BES |
7.09 |
6.4-7.8 |
| BICINE |
8.26 |
7.6-9.0 |
| bis-tris |
6.46 |
5.8-7.2 |
| BIS-TRIS propane |
6.80, 9.00 |
6.3-9.5 |
| borate |
9.23, 12.74, 13.80 |
8.5-10.2 |
| CABS |
10.7 |
10.0-11.4 |
| cacodylate |
6.27 |
5.0-7.4 |
| CAPS |
10.4 |
9.7-11.1 |
| CAPSO |
9.6 |
8.9-10.3 |
| carbonate (pK1) |
6.35 |
6.0-8.0 |
| carbonate (pK2) |
10.33 |
9.5-11.1 |
| CHES |
9.5 |
8.6-10.0 |
| citrate (pK1) |
3.13 |
2.2-6.5 |
| citrate (pK2) |
4.76 |
3.0-6.2 |
| citrate (pK3) |
6.4 |
5.5-7.2 |
| DIPSO |
7.52 |
7.0-8.2 |
| EPPS, HEPPS |
8 |
7.6-8.6 |
| ethanolamine |
9.5 |
6.0-12.0 |
| formate |
3.75 |
3.0-4.5 |
| glycine (pK1) |
2.35 |
2.2-3.6 |
| glycine (pK2) |
9.78 |
8.8-10.6 |
| glycylglycine (pK1) |
3.14 |
2.5-3.8 |
| glycylglycine (pK2) |
8.25 |
7.5-8.9 |
| HEPBS |
8.3 |
7.6-9.0 |
| HEPES |
7.48 |
6.8-8.2 |
| HEPPSO |
7.85 |
7.1-8.5 |
| histidine |
1.70, 6.04, 9.09 |
5.5-7.4 |
| hydrazine |
8.1 |
7.5-10.0 |
| imidazole |
6.95 |
6.2-7.8 |
| malate (pK1) |
3.4 |
2.7-4.2 |
| malate (pK2) |
5.13 |
4.0-6.0 |
| maleate (pK1) |
1.97 |
1.2-2.6 |
| maleate (pK2) |
6.24 |
5.5-7.2 |
| MES |
6.1 |
5.5-6.7 |
| methylamine |
10.66 |
9.5-11.5 |
| MOBS |
7.6 |
6.9-8.3 |
| MOPS |
7.14 |
6.5-7.9 |
| MOPSO |
6.87 |
6.2-7.6 |
| phosphate (pK1) |
2.15 |
1.7-2.9 |
| phosphate (pK2) |
7.2 |
5.8-8.0 |
| phosphate (pK3) |
12.33 |
|
| piperazine (pK1) |
5.33 |
5.0-6.0 |
| piperazine (pK2) |
9.73 |
9.5-9.8 |
| piperidine |
11.12 |
10.5-12.0 |
| PIPES |
6.76 |
6.1-7.5 |
| POPSO |
7.78 |
7.2-8.5 |
| propionate |
4.87 |
3.8-5.6 |
| pyridine |
5.23 |
4.9-5.9 |
| pyrophosphate |
0.91, 2.10, 6.70, 9.32 |
7.0-9.0 |
| succinate (pK1) |
4.21 |
3.2-5.2 |
| succinate (pK2) |
5.64 |
5.5-6.5 |
| TABS |
8.9 |
8.2-9.6 |
| TAPS |
8.4 |
7.7-9.1 |
| TAPSO |
7.61 |
7.0-8.2 |
| taurine (AES) |
9.06 |
8.4-9.6 |
| TES |
7.4 |
6.8-8.2 |
| tricine |
8.05 |
7.4-8.8 |
| triethanolamine (TEA) |
7.76 |
7.0-8.3 |
| Trizma (tris) |
8.06 |
7.5-9.0 |
|
|
|
|
