4-Hydroxyethylpiperazineethanesulfonic acid, referred to as HEPES, CAS No. 7365-45-9, is usually used as a biological buffer in biochemical experiments. It has properties similar to EPPS and is commonly used for pH-sensitive proteins and enzymes. research work.
Physical and chemical properties: HEPES
Molecular formula: C8H18N2O4S
Molecular weight: 238.31
Status: crystalline powder
pKa:7.45-7.65
Buffer range: 6.8-8.2
Structure:
Purity: greater than 99%
Use concentration: 10-50mmol/L
Depending on the application, HEPES buffers are subject to two commonly used buffer systems:
HEPES buffer solution: HEPES + NaOH (500mL): 119.15g HEPES is dissolved in 400mL distilled water, add 0.5~1M NaOH aqueous solution to adjust at least the required pH, pay attention to the effective pH buffer range is 6.8-8.2, and then use distilled water to make volume To 500mL;
2. HEPES buffered salt solution: HEPES 6.5g, NaCl 8.0g, Na2HPO4·7H2O 0.198g, adjust the pH value with 0.5M NaOH aqueous solution, and make the volume to 500mL.
3.2×HEPES buffered salt solution: Dissolve 1.6g of NaCl, 0.074g of KCl, 0.027g of Na2HPO4.2H2O, 0.2g of glucan or dextran and 1g of HEPES in 90ml of distilled water, and adjust to the required pH with 0.5M of NaOH Value, then dilute to 100ml with distilled water. In the cell-cell adhesion experiment, it contains calcium and magnesium ions; HA cell culture solution does not contain calcium and magnesium ions, but contains BSA.
The advantages of HEPES buffer:
1. Unlike PEcine, HEPES does not contain coordination groups and cannot form stable complexes with most metal ions. It is suitable for buffers in solution systems containing metal ions.
2. HEPES has very good water solubility, and the buffer range is close to neutral. Although PIPES does not form a complex with most metal ions, PIPES can form free radicals, so it is not suitable for redox systems and has relatively large ions. Strength, PIPES is more acidic.
3. HEPES has no toxic and side effects on cells at low concentration, and can control a constant pH range for a long time. The final concentration is 10-50mmol/L, and the general culture medium contains 20mmol/L HEPES to achieve buffering capacity. Therefore, it is commonly used in HA solution, cell culture solution, virus preservation solution and even skin care products.
Among the biological buffers, EPPS and PIPES are similar in properties to HEPES. They are used as buffers for different experiments, and sometimes can be replaced with each other. Desheng is a manufacturer of buffers. It has more experience in the production and sales of various buffers. Partners are welcome to visit and guide!
