Potentiometric Determination of Oxymetazoline Hydrochloride Using Modified Carbon Paste Electrodes

Two carbon paste electrodes for oxymetazoline hydrochloride were constructed based on ion pair complexes of this drug, with sodium tetraphenylborate (NaTPB) or ammonium reineckate, using dibutyl phthalate and dioctyl phthalate as solvent mediators, respectively. The developed electrodes displayed a fast, stable response over the concentration range from 3.98x10 to 1x10 M oxymetazoline hydrochloride, with a near-nernstian slope of 59.0, 58.2 mV of concentration decade and a limit of detection (LOD) of 3.31x10 and 3.72x10 M, in the oxymetazoline-tetraphenylborate and oxymetazoline-reineckate cases, respectively. The developed electrodes have been successfully applied for oxymetazoline hydrochloride determination in the Afrin nasal drop pharmaceutical formulation.