Square-wave voltammetric determination of acetylsalicylic acid in pharmaceutical formulations using a boron-doped diamond electrode without the need of previous alkaline hydrolysis step

In this paper the determination of acetylsalicylic acid (ASA) in pharmaceutical formulations using square-wave voltammetry (SWV) and a boron-doped diamond electrode (BDD) is described. By this proposed method, ASA is directly determined in a 0.01 mol L-1 H2SO4 solution without the need of a previous time-consuming alkaline hydrolysis step. A single oxidation peak at a potential of 1.97 V vs. Ag/AgCl (3.0 mol L-1 KCl) with the characteristics of an irreversible reaction was obtained. The obtained analytical curve is linear in the ASA concentration range 2.50 × 10-6-1.05 × 10-4 mol L-1, with a detection limit of 2.0 µmol L-1. The obtained relative standard deviation was smaller than 1.4% for a 45 µmol L-1 ASA solution (n = 10). The proposed method was applied with success in the determination of ASA in several pharmaceutical formulations; the obtained results were in close agreement, at a 95% confidence level, with those obtained using an official method of the British Pharmacopoeia.