HEPES Free Acid (N-[2-Hydroxyethyl] piperazine-N'- [2-ethanesulfonic acid])

HEPES is a biological buffer (zwitterionic) designed by Good, et al., and typically referred to as Good's buffer useful in cell culture media formulations. Selection of biological buffer systems should include the following criteria: exclusion by biological membranes, low absorption between 240 and 700nm, chemically stable, and stable to temperature and concentration changes. Synonym: N-[2-Hydroxyethyl]piperazine-N'-[2-ethanesulfonic acid], CAS No: 7365-45-9, Molecular Formula: C8H18N2O4S, Molecular Weight: 238.31, Appearance: White, crystalline powder, Purity: >99.0%, Identity (IR): Conform to reference, Solubility: Colorless, clear, complete, A260nm (1M): <0.05, A280nm (1M): <0.05, A405nm (1M): <0.05, pH: 5.2±0.5 , pKa1: ~3, pKa2: 7.55±0.2, Water (KF): <0.5%, Residue on Ignition: <0.5%, Heavy Metals: <0.001%, RNase, DNase, Protease: None Detected, Endotoxin: <1EU/ml, Certificate of Origin: China, Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological. Toxicity and Hazards: All products should be handled by qualified personnel only, trained in laboratory procedures.