| pKa Values of Common Buffers
Buffer
|
pKa
|
| H3PO4 / NaH2PO4
(pKa1) |
2.12 |
| Glycine (pKa1) |
2.34 |
| Citric acid (pKa1) |
3.13 |
| Acetic acid |
4.75 |
| Citric acid (pKa2) |
4.76 |
| MES |
6.15 |
| Cacodylic acid |
6.27 |
| H2CO3 / NaHCO3
(pKa1) |
6.37 |
| Citric acid (pKa3) |
6.40 |
| Bis-Tris |
6.50 |
| ADA |
6.60 |
| Bis-Tris Propane (pKa1) |
6.80 |
| PIPES |
6.80 |
| ACES |
6.90 |
| Imidazole |
7.00 |
| BES |
7.15 |
| MOPS |
7.20 |
| NaH2PO4 / Na2HPO4
(pKa2) |
7.21 |
| TES |
7.50 |
| HEPES |
7.55 |
| HEPPSO |
7.80 |
| Triethanolamine |
7.80 |
| Tricine |
8.10 |
| Tris |
8.10 |
| Glycine amide |
8.20 |
| Bicine |
8.35 |
| Glycylglycine (pKa2) |
8.40 |
| TAPS |
8.40 |
| Bis-Tris Propane (pKa2) |
9.00 |
| Boric acid (H3BO3
/ Na2B4O7) |
9.24 |
| CHES |
9.50 |
| Glycine (pKa2) |
9.60 |
| NaHCO3 / Na2CO3
(pKa2) |
10.25 |
| CAPS |
10.40 |
| Piperidine |
11.12 |
| Na2HPO4
/ Na3PO4 (pKa3) |
12.67 |
This table adapted from:
http://www.science.smith.edu/departments/Biochem/Biochem_353/Common_Buffers.html
|