TAPSO

white powder

TAPSO is a zwitterionic biological buffer often used as a buffering agent in biological and biochemical research. It has a pKa value of 7.635 (I=0, 25°C) and can be used to make buffer solutions in the pH range 7.0-8.2. As an Good'buffer, TAPSO contains Tris groups and exhibits quite reactive activity with zwitterionic glycine peptides[1]. TAPSO can serve as good stabilizers for the globular protein BSA, in the aqueous solutions[2].The solubilities of TAPSO increase with increasing concentration of the salts (salting-in effect)[3].

N-Tris(hydroxymethyl)methane-2-hydroxypropanesulfonic acid was prepared as follows: a mixture of 242.28 g (2 mol) of tris(hydroxymethyl)aminomethane, 500 ml of water and 196.5 g (1 mol) of sodium 3-chloro-2-hydroxypropanesulphonate was charged into a 1-liter 2-necked flask fitted with a stirrer and condenser. The mixture was stirred vigorously at reflux for 3 hours. After cooling to 25C, the solution was allowed to pass through a Dowex 50, hydrogen form cation exchange resin column to remove the sodium cation and form a free acid. The eluate from the column was evaporated under vacuum to a thick oil. After dilution with alcohol, the product was crystallized from the solution, filtered and washed with alcohol and dried. 160 g of the white product N-tris(hydroxymethyl)methionine-2-hydroxypropanesulfonic acid was obtained.

[1] Gupta B, et al. Stability Constants for the Equilibrium Models of Iron(III) with Several Biological Buffers in Aqueous Solutions. Journal of Solution Chemistry, 2013; 42: 2296–2309.
[2] Gupta ;B, et al. Interactions of bovine serum albumin with biological buffers, TES, TAPS, and TAPSO in aqueous solutions. Process Biochemistry, 2013; 48: 1686-1696.
[3] Taha M, et al. New Insights into Buffer-Ionic Salt Interactions: Solubilities, Transfer Gibbs Energies, and Transfer Molar Volumes of TAPS and TAPSO from Water to Aqueous Electrolyte Solutions. Journal of Solution Chemistry, 2010; 39:1665–1680.