HEPES
From Wikipedia, the free encyclopedia
| HEPES | |
|---|---|
 |
|
| General | |
| Systematic name | 4-(2-hydroxyethyl)-1- piperazineethanesulfonic acid |
| Other names | HEPES |
| Molecular formula | C8H18N2O4S |
| Molar mass | 238.3012 g/mol |
| Appearance | white crystalline powder |
| CAS number | [] |
| Properties | |
| Density and phase | ? g/l, solid (25°C) |
| Solubility in water | 40 g/100 ml (20°C) |
| Melting point | >234-238°C (453-457K) |
| Acidity (pKa) | 3 and 7.55 |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Irritant. |
| NFPA 704 |
0
2
0
|
| Flash point | Non-flammable. |
| R/S statement | R: R36, R37, R38. S: S26, S36. |
| RTECS number | TY2900000 |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references |
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HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid ) is an organic chemical buffering agent that is widely used in cell culture to maintain physiological pH.
HEPES is recommended for the protection of frozen solutions of enzymes from freezing-induced pH changes.
Lepe-Zuniga et al. reported a phototoxicity of HEPES when exposed to ambient light by the production of hydrogen peroxide. For best repeatability of results it is then strongly advised to keep any HEPES containing solution in darkness as much as possible.
Fears that HEPES may serve as a nutrient source for aerobic bacteria have been shown to be unfounded.
[edit] References
- Toxicity of light-exposed Hepes media. Lepe-Zuniga JL, Zigler JS Jr, Gery I. Journal of Immunological Methods. 1987 Oct 23;103(1):145.
- Analysis of the cytotoxic effects of light-exposed HEPES-containing culture medium.
- Zigler JS Jr, Lepe-Zuniga JL, Vistica B, Gery I., In Vitro Cell Dev Biol. 1985 May;21(5):282-7.
