How does tris(hydroxymethyl)aminomethane dissociate in water

Tris is one of the most widely used biological buffers in biochemical experiments. It is a non-metal ion pH buffer, since it will not be added to the system when adjusting the pH Bringing in metal ions, how does Tris dissociate in water?

Generally speaking, the biological buffer in biochemical experiments or biological experiments uses sodium hydroxide or potassium hydroxide to adjust the acid-base buffer range, which means that it will bring sodium or potassium ions, such as TAPS, HEPES, Bicine and so on.

Trimethylolmethylaminopropane sulfonic acid TAPS, when used as a buffer, is in the form of TAPS sodium salt, which dissociates or ionizes sodium ions in the solution. The same HEPES buffer and Bicine buffer contain Of sodium or potassium ions. But the buffer system of Tris can not bring metal ions into the reaction environment.

How does Tris dissociate

Tris is directly dissolved in water and is slightly alkaline, but compared to biochemical experiments, this alkaline is stronger, because most biochemical reactions occur in a near-neutral pH environment. The reason why Tris is alkaline is that it dissociates in water in a special way, and its molecule itself does not dissociate from ions, but the amino nitrogen atom in the Tris structure has more outer electrons, and one pair of electrons does not form. Bond, and the hydrogen ion or hydronium ion just has an empty electron orbit, it will adsorb the hydrogen ion.

Therefore, Tris does not break cations in water, but the whole molecule adsorbs hydrogen ions in the water and then forms cations. At the same time, the ionization balance of water is broken and will continue to be hydrolyzed, so that more and more hydroxide ions will be added, so the solution is obvious. There are not many alkaline reagents for the unique dissociation method like Tris. Tris can be regarded as a polyhydroxyamine, which is similar to ammonia, but it does not contain metals but can hydrolyze cations.

Tris's other name tromethamine (treatment of acidosis) also reflects its non-metallic but alkaline characteristics. However, Tris produced by Desheng is mainly used for biochemical experiments and organic synthesis, not for the preparation of tromethamine.