T 1900 (OTTO) p-Toluenesulphonic acid sodium salt, 95% Cas 657-84-1 - used as a supporting electrolyte for depositing polypyrrole membranes.T 1900 (OTTO) p-Toluenesulphonic acid sodium salt, 95% Cas 657-84-1 - used as a solute to study the performance of resin particles.