Jun 03, 2020
Citrate-Phosphate Buffer
- 1University of Manitoba
Protocol Citation: Neilier Junior 2020. Citrate-Phosphate Buffer. protocols.io https://dx.doi.org/10.17504/protocols.io.bfydjps6
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: May 05, 2020
Last Modified: June 03, 2020
Protocol Integer ID: 36581
Keywords: pH, Henderson-Hasselback, Biochemistry, Molecular Biology,
Abstract
A buffer solution has the function of resisting changes in pH even when adding powerful acids or bases. However, in the physiological environment the buffered system also provides cofactors for enzymatic reactions, critical salts and even essential nutrients for cells and tissues. Therefore, when trying to reproduce biological conditions in vitro, we must make the appropriate choice of the buffer. After all, it will provide the appropriate medium in which reactions will occur.
Materials
- Deionized Water
- pH Meter (sensitive)
- Citric Acid
- Dibasic Sodium Phosphate (dihydrate and heptahydrate)
Safety warnings
Wear personal protective equipment: gloves, lab coat and mask.
Before start
Organize your workspace.
Make sure all solutions and equipment are available.
Citrate-Phosphate Buffer
Citrate-Phosphate Buffer
Note
pH range: 2.6 to 7.0
(a) 0.1 M Citric acid; 19.21 g L-1 (M.W. 192.1 g mol-1)
(b) 0.2 M Dibasic sodium phosphate; 35.6 g L-1 (dihydrate; M.W. 178.0 g mol-1) or 53.6 g L-1 (heptahydrate; M.W. 268.0 g mol-1)
Mix citric acid and sodium phosphate solutions in the proportions indicated and adjust the final volume to 100 mL with deionized water.
| mL of Citric acid | 44.6 | 39.8 | 35.9 | 32.3 | 29.4 | 26.7 | 24.3 | 22.2 | 19.7 | 16.9 | 13.6 | 6.5 | |
| mL of Sodium phosphate | 5.4 | 10.2 | 14.1 | 17.7 | 20.6 | 23.3 | 25.7 | 27.8 | 30.3 | 33.1 | 36.4 | 43.6 | |
| pH | 2.6 | 3.0 | 3.4 | 3.8 | 4.2 | 4.6 | 5.0 | 5.4 | 5.8 | 6.2 | 6.6 | 7.0 |
Adjust the final pH using a sensitive pH meter