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 pK_a 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 pK_a, maximum water solubility and minimum solubility in all other solvents, minimal salt effects, minimal change in pK_a 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.

PIPES sodium salt buffer has been used:

• to prepare BRB80 buffer for imaging dynamic microtubules and single kinesin molecules through fluorescence microscopy
• as a component of PEM fixation solution
• to reconstitute red blood cells (RBCs) to study the effect of pH on 5-coordinate alpha-nitrosyl-hemoglobin (HbNO) stability