Many biochemical processes are markedly impaired by even small changes in the concentrations of free H+ ions. It is therefore usually necessary to stabilise the H+ concentration in vitro by adding a suitable buffer to the medium, without, however, affecting the functioning of the system under investigation. A buffer keeps the pH of a solution constant by taking up protons that are released during reactions, or by releasing protons when they are consumed by reactions.
This handout summarizes the most commonly used buffer substances and respective physical and chemical properties. Furthermore, it provides some practical tips for the preparation of buffer solutions regarding temperatur, titration (setting of pH value) and prevention of microbial contamination.
Fore more detailed information, the brochure "Biological Buffers" imparts basic knowledge on biological buffer substances and support in terms of selecting the best buffer substance for your assay system. Be aware of the fact that some buffers serve as substrate / inhibitor of enzymes (e.g. phosphate) or the temperature sensitivity of the pH of some buffers, especially Tris, probably the most frequently employed buffer substance.