Biological buffer solution is a kind of solution which can keep pH value relatively stable when adding a small amount of acid or base. It is usually composed of weak acid and its conjugated base or weak base and its conjugated acid buffer pair. Most cells can only move in a narrow pH range, so a buffer system is needed to resist the pH change in the metabolic process. Buffer is widely used in biochemical field. How to distinguish the quality of buffer solution? What characteristics should they have?
Package drawing of biological buffer
First of all, let's take a closer look at what a buffer is?
Buffer is an aqueous solution containing conjugated acids or bases. The pH range of the buffer is determined by its pKa value. The pKa value is defined as the pH value when 50% of the molecules are acidic and 50% are basic. A conventional principle of buffer solution is that its pH value should be within the range of 1 pH value unit about pKa value, so as to ensure its good buffer capacity. In this way, it can be ensured that there are enough molecules in both acid and basic structure to neutralize them when H + or Oh - is added. In this way, the buffer can prevent the change of protein stability caused by pH change.
Good buffer must have the following characteristics:
1. Water solubility
2. Chemical stability
3. Good buffering capacity in the required pH range
4. It has good compatibility with analytical and experimental conditions
5. It has good compatibility with other solutes
Many substances can be used in biological buffers. The most commonly used buffer components usually have a near neutral pKa value and can be used around the physiological pH range. Table 1 lists the four most commonly used biological buffers, their respective pH ranges, and their advantages and disadvantages that may affect the protein purification process. To ensure adequate buffer capacity, the concentration of these buffers is usually 25mm.
The effect of buffer solution is as follows
The function of buffer solution is to adjust the pH value of the solution within a limited range, so that the acidity of the solution to be measured meets the range specified by the analytical method. For example, phenol can react with 4-aminoantipyrine in alkaline medium and the presence of potassium ferricyanide to produce orange red antipyrine dye. In order to prevent the interference of aromatic amines, the pH value of 10 ± 0.2 is the most suitable. Therefore, it is necessary to add ammonia money chloride buffer solution into the solution to be tested, and adjust and control the pH value of the solution to be measured to 10.0 ± 0.2.
Where can I buy a good buffer?
Desheng can provide high-quality buffer for customers. Desheng has been focusing on the R & D and production of biological buffer, blood collection additive and chemiluminescence reagent for 15 years, and can freely adjust the concentration of buffer required according to customer demand.
In practical work, some analysts do not understand the mechanism of buffer solution. When the buffer solution prepared and used is not in accordance with the specified value, in order to make the buffer solution meet the requirements, the strong acid and alkali such as hydrochloric acid or sodium hydroxide are used to adjust the buffer solution, thinking that this can make the buffer solution reach the required pH value as soon as possible. However, the results obtained are counterproductive Although the pH value of such a solution is adjusted correctly, its buffer system is destroyed and its function is lost. Generally, the buffer solution is a pair of conjugates composed of weak acid and its weak acid salt or weak base and its weak base salt.
