Biological buffer is often used in biochemical research experiments, which is of great significance. It is a kind of regulatory solution that can resist the influence of a small amount of strong acids and bases, and maintain the pH value basically unchanged. Among them, Tris buffer, PBS buffer, caps buffer, mops buffer, taps buffer and EPPs buffer are frequently used. In this paper, the most commonly used Tris buffer solution and PBS buffer solution are compared and introduced from several aspects.
1. Buffer range
Tris is a weak base with molecular formula of c4h11no3, molecular weight of 121.14 and pKa of 8.1 at 25 ° C. The effective buffer range of Tris is between pH 7.0 and 9.2. The commonly used pH values in biochemical experiments are 6.8, 7.4, 8.0 and 8.8. Tris has been widely used in the preparation of buffer solutions in biochemistry and molecular biology experiments, even more than phosphate buffer solutions.
Phosphate buffer (PBS) is a kind of salt solution with phosphate as pH buffer and sodium chloride as osmotic pressure equilibrium. Sodium phosphate buffer and potassium phosphate buffer are commonly used. Because of their secondary dissociation and wide pH range, they are widely used in biochemical research.
2. Configuration method
There are two ways to prepare Tris HCl buffer solution: prepare Tris and HCl solution respectively, and then mix them according to the volume listed in the common table. However, because the diluted hydrochloric acid of standard concentration is not easy to prepare, another method is commonly used: take the configuration of Tris HCl buffer as an example: first dissolve Tris alkali in 950 ml ~ 970 ml deionized water, add HCl while stirring, measure the pH value of solution with pH meter to the required pH value, and then add water.
Preparation method of phosphate buffer solution: NaCl, KCl, KH2PO4 and K2HPO4 are dissolved in 800 ml distilled water, the pH value of the solution is adjusted to 7.4 with HCl, and finally the volume is adjusted to 1 l with distilled water. Store in refrigerator at 4 ℃. It should be noted that the concentration usually refers to all phosphate concentration in buffer solution, not Na + or K + concentration. Na + and K + are only used to adjust osmotic pressure. When preparing phosphate buffer solution, potassium salt is better than sodium salt. Sodium salt is not easy to dissolve at low temperature, while potassium salt has higher solubility.
3. Field of use
Tris buffer solution In the electrophoretic buffer, glycine buffer system was used to stabilize the pH value; the Tris-HCl buffer system was used to stabilize the pH value in the gel; it was widely used as a solvent for nucleic acids and proteins; the low ionic strength of the Tris buffer could also be applied to the formation of the intermediate fiber of the nematode; the TE buffer was added into the Tris salt acid buffer to make DNA stable and stored; and pH was adjusted. The "Tae buffer" can be obtained by changing the acid solution to acetic acid, and the "tbe buffer" can be obtained by changing the acid solution to boric acid. These two buffers are often used in nucleic acid electrophoresis experiments.
Phosphate buffer solution is usually used to dilute the active biological agents. The reason is that it has the buffering effect of salt balance and adjusting the appropriate pH value. Distilled water does not have the function of salt balance, which will destroy the structure and biological characteristics of biological protein; physiological saline does not have the function of adjusting pH, and it can not guarantee the complete and active substances to participate in the biological reaction under the optimal conditions, so PBS is the first choice. Of course, PBS is not omnipotent. Some bioactive substances need higher conditions, so it is necessary to add more components into the equilibrium buffer to maintain the best conditions to ensure that the bioactive substances maintain their most complete characteristics. Therefore, PBS is mainly used in cell experiments, and its buffer range is most suitable in neutral.
In biochemistry experiments, we should choose the buffer solution carefully, not only considering the buffer range of the buffer solution, but also considering the use environment of the buffer solution. Hubei new Desheng materials has been specializing in the production and development of biological buffer for many years. Desheng has an independent R & D team and has rich practical experience in product R & D and production. At present, the biological buffer and other products produced by Desheng have been sold to many countries around the world, and have received good reviews and re purchase. We have reached long-term cooperation with many foreign customers. If you are interested in understanding, you can call to consult, Desheng welcome your call.
