Voltammetric oxidation and determination of atorvastatin based on the enhancement effect of cetyltrimethyl ammonium bromide at a carbon paste electrode

An electrochemical method has been described for the voltammetric oxidation and determination of an antihyperlipoproteinemic drug, atorvastatin (ATOR), at a carbon paste electrode (CPE) in the presence of an enhancing agent, cetyltrimethyl ammonium bromide (CTAB) using cyclic and differential pulse voltammetry (DPV). The results indicated that the voltammetric response of ATOR was improved distinctly in the low concentration of CTAB, suggesting that CTAB exhibits noticeable enhancement effect to the determination of ATOR. The dependence of current on pH, concentration and scan rate were investigated to optimize the experimental conditions for the determination of ATOR. The anodic peak was characterized and the process was adsorption-controlled. The number of electrons transferred in the oxidation process was calculated and a plausible oxidation mechanism was proposed. In the range of 0.05–10 μM, the current measured by DPV presents a good linear property as a function of the concentration of ATOR with a detection limit of 4.08 nM with good selectivity and sensitivity. The proposed method was successfully applied to ATOR determination in pharmaceutical samples and urine as a real sample. This method can be employed in clinical analysis, quality control and routine determination of drugs in pharmaceutical formulations.