PIPES

piperazine-N,N’-bis(ethanesulfonic acid); 1,4-piperazinediethanesulfonic acid, CAS NUMBER: 5625-37-6, Sigma P6757

A Good buffer [1][2][3].

• pK_a at 25C of 6.8 (a second one at pH 3 is not of interest)
• usable buffering range of 6.1 to 7.5
• molecular weight 302.4
• ΔpK_a/ΔT = -.0085

Buffers are typically 0.5 M, prepared by neutralizing PIPES with sodium hydroxide. PIPES is essentially insoluble until it is neutralized.

1. Good NE, Winget GD, Winter W, Connolly TN, Izawa S, and Singh RM. Hydrogen ion buffers for biological research. Biochemistry. 1966 Feb;5(2):467-77. DOI:10.1021/bi00866a011 |
2. Good NE and Izawa S. Hydrogen ion buffers. Methods Enzymol. 1972;24:53-68. DOI:10.1016/0076-6879(72)24054-x |
3. Blanchard JS. Buffers for enzymes. Methods Enzymol. 1984;104:404-14. DOI:10.1016/s0076-6879(84)04107-0 |

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