HEPES is 4-hydroxyethyl piperazine ethanesulfonic acid in Chinese, CAS number is 7365-45-9, pH buffer range is 6.8-8.2, pKa value is 7.5 at 25 ℃. HEPES Na is n - (2-hydroxyethyl) piperazine-n '- (2-ethanesulfonic acid) sodium salt, its CAS number is 75277-39-3. HEPES and HEPES Na are very important biological buffers, which are widely used in biopharmaceutical, medical diagnosis and other fields.
Packaging of biological buffer series products
HEPES is a kind of amphoteric buffer, which is used in cell culture medium and protein research for various types of organisms. It can also be used in biochemical diagnostic kit, DNA / RNA extraction kit and PCR diagnostic kit. Because of its non-toxic effect on cells and the ability to control the constant pH range for a long time, HEPES is often used as cosmetic additive, active agent, peeling agent and promoter Through the role of the agent.
Difference between HEPES and HEPES Na: HEPES Na, also known as organic HEPES base, is a conjugated acid-base relationship with HEPES. They are essentially the same, but the pH of the two substances after dissolution is different.
The preparation methods of HEPES were as follows
About the preparation of HEPES buffer solution, according to the use of preparation, one is pure HEPES + NaOH, the other is HEPES + salt. Various preparation methods are summarized as follows:
1、 Preparation of 500 ml 1 m HEPES, pH = 7.0, stock solution
Dissolve 119.15 g HEPES in 400ml distilled water, add 0.5 ~ 1m NaOH aqueous solution to adjust at least the required pH (the effective pH range of HEPES is 6.8 ~ 8.2), then fix the volume to 500ml with distilled water and store at 4 ℃.
2、 HEPES buffer formula with small amount of salt (500ml)
HEPES 6.5g, NaCl 8.0g, na2hpo4.7h2o 0.198g, adjust the pH value with 0.5m NaOH solution, and finally fix the volume.
3、 Preparation of 2 × HEPES buffer salt solution
Dissolve 1.6g NaCl, 0.074g KCl, 0.027g na2hpo4.2h2o, 0.2g dextran and 1g HEPES in 90ml distilled water, adjust to the required pH value with 0.5m NaOH, and then fix the volume to 100ml with distilled water.
The preparation method of HEPES Na was as follows
HEPES Na can be synthesized by 4-hydroxyethyl piperazine and sodium vinyl sulfonate, or by high pressure synthesis of hydroxyethyl sulfonic acid, sodium hydroxide and 4-hydroxyethyl piperazine. At present, the most widely used preparation method that meets the requirements of biological buffers is the reaction of HEPES with NaOH to produce HEPES Na. The specific preparation steps are as follows:
Under the protection of nitrogen, HEPES with purity between 90-99% and NaOH solid or solution were reacted for 0.2-1 hour at 20-100 ℃. After the reaction, the obtained product was decolorized, filtered, concentrated, dehydrated, crystallized, washed and dried to obtain HEPES Na.
This method is simple and easy to operate, and the yield and purity of HEPES Na product are high, which can meet the purity requirements of biological buffer.
Desheng has 15 years of experience in developing and producing series products of biological buffers (Tris, HEPES, caps, mops, pipes). Desheng has deep research on blood vessel additives (heparin lithium, heparin sodium, dipotassium, Tripotassium), chromogenic reagents (toos, Maos, tops, Alps), chemiluminescence reagents (luminol, isoluminol, acridine ester). Desheng has checked the production and packaging of selected materials layer by layer, and insisted on improving the quality of products for customers Provide high quality raw materials for products.
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