Formation of a descending pH gradient in a column filled with a carboxylic cation exchanger

Descending pH gradients in a colum filled with an SM-52 carboxylic cation-exchange sorbent based on cellulose were formed using the chromatofocusing technique. A 10 mM tris-HCl solution was used as the starting buffer solution, and a Polybuffer-96 solution (1:20), as the eluent forming the pH gradient. It was established that linear pH gradients in the cation-exchange system were obtainable due to the addition of a strong electrolyte (NaCl) to the starting solution and to the eluent.