Determination of potassium guaiacolsulfonate by ion-pairing partition chromatography

Potassium guaiacolsulfonate, a highly polar, acidic substance, is readily eluted by chloroform from a pH 4.5 Celite column in the form of its ion-pair with trihexylamine, thereby effecting facile separation from other pharmaceuticals. The sulfonic acid is then back-extracted into aqueous alkali and determined spectrophotometrically. Assay of standard solutions by this procedre averaged 100.44 plus or minus 0.81%. The method was applied successfully to 4 commercial cough preparations containing a variety of other drugs.