TES is used to make buffer solutions. It has a pKa value of 7.550 (I=0, 25°C). It is one of the Good's buffers and can be used to make buffer solutions in the pH range 6.8–8.2. It is one of the components of Test yolk buffer medium used for refrigeration and transport of semen.
Biological buffers, like tris, are important because they can maintain a stable pH despite influences that might otherwise shift the pH. Tris(hydroxymethyl) aminomethane, with a pKa of 8.1, is an effective buffer between pH 7 and 9. Because of its neutral range, tris is a commonly used buffer in biological labs
It is used to prevent any change in the pH of a solution, regardless of solute. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. For example, blood in the human body is a buffer solution.