Voltammetric Sensor Based on Boron-Doped Diamond Electrode for Simultaneous Determination of Paracetamol, Caffeine, and Aspirin in Pharmaceutical Formulations

In this paper, a method was developed for the individual and simultaneous determination of paracetamol (PAR), caffeine (CAF), and aspirin (ASA), based on the oxidation of these compounds at a cathodically pretreated boron-doped diamond electrode without any chemical modification. The electrochemical behavior of these three molecules was investigated employing cyclic voltammetry and square-wave adsorptive stripping voltammetry. Using stripping voltammetry in phosphate buffer at pH 2.5, the three compounds can well separate from each other with the potential differences of 0.71, 1.27, and 0.56 V among PAR-CAF, PAR-ASA, and CAF-ASA, respectively, which are large enough to determine PAR, CAF, and ASA individually and simultaneously. After the optimization of analytical conditions employing this electrode in phosphate buffer (pH 2.5), the adsorptive stripping peak currents for the three molecules were found to be linearly with their concentrations in the range of 5-125 mu g mL(-1) with the detection limits of 0.597, 0.277, and 1.310 mu g mL(-1) for PAR, CAF, and ASA, respectively. The presented method was provided a fast, sensitive, and simple approach to the determination of PAR, CAF, and ASA in the pharmaceutical formulations. The results obtained were statistically analyzed and compared with those obtained by applying the high-performance liquid chromatographic method with diode-array detection.