Electroanalytical method for the determination of methylparaben

A gold electrode (GE) was used for the electroanalytical determination of methylparaben in a pharmaceutical product and urine sample by cyclic, linear sweep and square-wave voltammetric techniques. The oxidation of methylparaben is irreversible and exhibits a diffusion controlled process. The oxidation mechanism was proposed. The dependence of the current on pH, the concentration and scan rate was investigated to optimize the experimental conditions for the determination of methylparaben. It was found that the optimum buffer for the determination of methylparaben is pH of 7.0, a physiological pH. In the range of 0.04 to 1.00 mM, the current measured by square wave voltammetry presents a good linear property as a function of the concentration of methylparaben with limit of detection 1.71 μM and limit of quantification 5.70 μM. In addition, the reproducibility (RSD of 1.06%), precision (RSD of 1.27%) and accuracy (98.05-103.4%) of the method were checked as well. Electroanalytical determination of methylparaben in pharmaceutical products and urine was done using only square wave voltammetry. The method finds its applications in quality control laboratories.