Biobuffer is a solution that can keep the pH value of the solution relatively stable when adding a small amount of acid or alkali. Most cells can only operate in a very narrow pH range, and a buffer system is needed to resist the pH changes in the metabolic process. In biochemical research, buffer solution is often used to maintain the ph of the experimental system. 1. Phosphate buffer Phosphate buffer is the most widely used buffer. Due to secondary dissociation, the buffer has a wide pH range and can be configured with acidic, alkaline and neutral buffers of different pH values: Acidic buffer can be prepared by using NaH2PO4 or KH2PO4 directly, pH range is 1~5; Alkaline buffer can be directly used Na2HPO4 or K2HPO4