HEPES buffer



🏾 Introduction

HEPES is a general purpose buffering agent widely used in biochemistry and molecular biology to maintain physiological pH (pH range 6.8-8.2).

It is a zwitterionic organic compound, it tends to capture or release H+ ions depending on the pH value of the aqueous solution where they are found. The zwitterion is in equilibrium with the cation and the corresponding anion.

HEPES Buffer is categorized as "Good buffers", which is derived from a set of buffers described by Dr. Norman Good et al. (Good et al., Biochemistry 1966).

Hepes free acid

CAS number 7365-45-9
Molecular mass 238.30 g/Mol
Formula C8H18N2O4S
Synonyms N-2-Hydroxyethylpiperazine-N'-2-ethanesulfonic acid, N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic) acid

HEPE sodium saltS

CAS number 75277-39-3
Molecular mass 260.29 g/Mol
Formula C8H17N2O4SNa
Synonyms sodium;2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonate

🏾 HEPES Buffer Applications and Uses

A buffer is a solution that contains an acid and a base or a salt. Its main purpose is to maintain the concentration of hydrogen ions at an ideal level for specific purposes, such as a bacterial culture. Just like other types of chemical buffers, HEPES buffer maintains the ion concentration of a solution at an ideal level (= ideal pH level) for a certain use. Specifically, HEPES buffer is used to maintain ideal conditions for cell culture


🏾 Properties

HEPES is a general purpose buffer. It is water soluble, does not interfere with biological processes or biological membranes (penetration, solubilization, surface adsorption, etc.), has a known tendency to form complexes with metal ions, is non-toxic and has very low U.V. absorption at wavelength > 260 nm.

HEPES powder is high temperature resistant with its melting point reaching 200℃, so it will not degrade by autoclaving, or you can filter the HEPES buffer solutions using a syringe filter from 0.2 micrometer.

The aqueous solution of HEPES should be stored away from light. exposure to ambient light for three hours would produce cytotoxic hydrogen peroxide


References:

  1. J Jeffrey Morris - Continuous hydrogen peroxide production by organic buffers in phytoplankton culture media
  2. hopaxfc - HEPES handling and storage tips that you must know
  3. goldbio - HEPES, Free Acid
  4. goldbio - HEPES, Sodium Salt
  5. Sigma - HEPES solution Cell Culture Tested
  6. W Lang - Physiological HEPES buffer proposed as a calibrator for pH measurement in human blood
  7. fisherscientific - Acide libre HEPES
  8. W Lang - Physiological HEPES buffer proposed as a calibrator for pH measurement in human blood
  9. Reagent -
  10. Biowest - HEPES Buffer Solution
  11. Uptima - HEPES Buffer
  12. Capricorn Scientific - HEPES Buffer Solution