Merck, P2949-500G, PIPES sodium salt

1, 4-piperazinediethanesulfonic acid (PIPES) is a zwitterionic buffer that belongs to the group of the ethanesulfonic acid buffer series, first introduced by Good et al., It is a non-toxic buffer used in cell culture and tissue fixation for electron microscopy and other biological applications. PIPES don’t interact with metal ions. Since its pKₐ at 37°C is near physiological pH, it has been used as a buffering substance in biological, biochemical, and environmental studies. PIPES is developed to meet certain criteria: midrange pKₐ, maximum water solubility and minimum solubility in all other solvents, minimal salt effects, minimal change in pKₐ with temperature, chemically and enzymatically stable, minimal absorption in visible or UV spectral range and easily synthesized. Buffers can be prepared by adding a solution of the base to PIPES-free acid, titrating to the appropriate pH, or by mixing equimolar solutions of the monosodium salt and the disodium salt, titrating to the appropriate pH.