Tris saturated phenol: 1. Take out the re steamed phenol from the refrigerator and place it in a 68 water bath at room temperature to dissolve it. Do not put it in a 68 â?? water bath immediately to prevent the glass from cracking; 2. Add 8-hydroxyquinoline to 0.1% and �² - mercaptoethanol to 0.2% (stock solution 14.4mol/ml), mix well, the solution turns yellow, and pour into the separating funnel (it can also be carried out in a beaker); 3. Add 1mol / ml tris (ph8.0) of the same solvent, mix it repeatedly, and let it stand still until it is layered; release the Yellow phenol solution in the lower layer and discard the upper layer; 4. Add solid Tris about 1g / 100ml phenol, shake well and remove the aqueous phase; 5. Add 0.1mol/mltris (ph8.0) to balance several times until pH is 8.0; 6. Add 0.1mol/mltris (ph8.0) and store in brown bottle for 4 degrees; 7. If yellow disappears or pink, it cannot be used. Tris saturated phenol is toxic and has a strong irritant effect on skin and human body, so it needs to be operated in the fume hood. Avoid harm, safety first.