Voltammetric determination of salicylic acid in pharmaceuticals formulations of acetylsalicylic acid

The electrochemical oxidation of salicylic acid (SA) has been studied on a glassy carbon electrode using cyclic voltammetry and differential pulse voltammetric (DPV) method. SA gives a single irreversible oxidation wave over the wide pH range studied. The irreversibility of the electrode process was verified by different criteria. The mechanism of oxidation is discussed. Using differential pulse voltammetry, SA yielded a well-defined voltammetric response in Britton-Robinson buffer solution, pH 2.37 at 1.088 V (versus Ag/AgCl). The method was linear over the SA concentration range: 1-60 μg ml⁻¹. The method was successfully applied for the analysis of SA as a hydrolysis product, in solid pharmaceutical formulations containing acetylsalicylic acid (ASA).