Determinação voltamétrica de analitos de interesse farmacêutico utilizando um eletrodo de diamante dopado com boro

Abstract

The development of electroanalytical procedures for acetylsalicylic acid (ASA), propranolol (PROP), atenolol and sildenafil (Viagra®) in pharmaceutical formulations using a boron doped diamond (BDD) electrode, square wave and differential pulse voltammetric techniques are described. ASA was directly determined in a 0.01 mol L-1 H2SO4 solution without the need of a previous alkaline hydrolysis step with the BDD electrode and square wave voltammetry (SWV). The analytical curve was linear in the ASA concentration range 2.5 × 10-6 to 1.0 × 10-4 mol L-1 with a detection limit of 2.0 × 10-6 mol L-1. Then, the analytical determination of PROP was carried out in a 0.1 mol L-1 H2SO4 solution using a cathodically pre-treated BDD electrode employing SWV. The analytical curve was linear in the PROP concentration range 2.0 × 10-7 to 9.0 × 10-6 mol L-1 with a detection limit of 1.8 × 10-7 mol L-1. The determination of atenolol was accomplished in 0.5 mol L-1 NaNO3 (pHcond 1.1 adjusted with concentrated HNO3) on a cathodically pre-treated BDD electrode employing SWV. The analytical curve was linear in the atenolol concentration range from 2.0 × 10-6 to 4.1 × 10-5 mol L-1 with a detection limit of 9.3 × 10-7 mol L-1. Finally, a procedure for the determination of sildenafil in 0.1 mol L-1 H2SO4 on a cathodically pre-treated BDD electrode employing differential pulse voltammetry was developed. The analytical curve was linear in the sildenafil concentration range 7.3 × 10-7 to 7.3 × 10-6 mol L-1 with a detection limit of 4.8 × 10-7 mol L-1.