Within the scope of the USP monograph modernization, potassium is determined in potassium bicarbonate effervescent tablets for oral suspension applying cation chromatography with direct conductivity detection. The separation is performed on a Metrosep C 6 - 150/4.0 column (L76). All acceptance criteria are fulfilled. The USP41 monograph for “Potassium bicarbonate effervescent tablets for oral suspension” performs the assay of potassium by atomic absorption spectroscopy.