PRODUCT IDENTIFICATION

CLASSIFICATION

Buffer

EXTRA NOTES

PHYSICAL AND CHEMICAL PROPERTIES

REFRACTIVE INDEX

EXTERNAL LINKS & GENERAL DESCRIPTION

Wikipedia Linking

Google Scholar Search

Drug Information Portal (U.S. National Library of Medicine) - HEPES

PubChem Compound Summary - HEPES

http://www.ebi.ac.uk/chebi/ -  HEPES

http://www.ncbi.nlm.nih.gov/ -  HEPES

Material Safety Data Sheet

http://www.sigmaaldrich.com/
HEPES is used in many media because it has more buffering capacity in the physiologic pH range of 7.2 - 7.4 at 37°C than sodium bicarbonate. It is commonly added at concentrations between 10 mM and 25 mM. Higher levels cause cytotoxicity. Because bicarbonate is nutritionally necessary for most cells, HEPES should be added in addition to, not in place of, sodium bicarbonate.

Local:
Buffer is a substance, generally a solution, that can keep its pH constant, despite the addition of strong acids or strong bases and external influences of temperature, pressure, volume, redox potential. Buffer prevents change in the concentration of another chemical substance, e.g., proton donor and acceptor systems that prevent marked changes in hydrogen ion concentration (pH). Many acid-base reactions take place in living organisms. However, for organisms to perform certain vital functions, the body fluids associated with these functions must maintain a constant pH. For example, blood must maintain a pH of close to 7.4 in order to carry oxygen from the lungs to cells; blood is therefore a powerful buffer. The commonest buffer in chemical solution systems is the acid-base buffer.

• Bicarbonate buffer; a buffer system composed of bicarbonate ions and dissolved carbon dioxide; in the body, this system is an important factor in determining the pH of the blood as the concentration of bicarbonate ions is regulated by the kidneys and of carbon dioxide by the respiratory system.
• Cacodylate buffer; one containing an organic arsenical salt, used in preparing fixatives for electron microscopy.
• Phosphate buffer,   a buffer system composed of KH₂PO₄ and Na₂HPO₄; in the body, it is important in regulating the pH of the renal tubular fluids; when 0.025 molal (equimolal of the potassium and sodium salts), the pH is 6.865 at 25 C.
• Protein buffer,   a buffer system involving proton donor and proton acceptor groups of the amino acid residues of proteins.
• TRIS buffer (tromethamine): an amine base used intravenously as an alkalizer for the correction of metabolic acidosis. The pH values of all buffers are temperature- and concentration-dependent. For Tris buffers, pH increases about 0.03 unit per C temperature decrease, and decreases 0.03-0.05 unit per ten-fold dilution.
• Veronal buffer; a barbital buffer commonly used in the preparation of fixatives for electron microscopy.

• Tissue culture
• Phosphorylation and Photophosphorylation
• Fixative Transmission Electron Microscopy
• Protein synthesis
• Preventing binding to non-receptor materials

APPEARANCE

99.5% min

RESIDUE ON IGNITION

0.1% max

LOSS ON DRYING

1.0% max

pH

HAZARD OVERVIEW

Not known

RISK PHRASES

SAFETY PHRASES

PRICE INFORMATION