Novel Electrochemical Determination of Atorvastatin by Monitoring the Suppression of a Lead Probe

Abstract

This work presents the development of a new electrochemical method for the indirect determination of atorvastatin (ATO) using Pb²⁺ as a probe at a potential value of -0.40 V. The square-wave voltammetric parameters such as the frequency (50 Hz), amplitude (100 mV) and step size (2 mV) were adjusted to obtain the most symmetrical and intense probe peak. The influences of pH (2.0), background electrolyte composition (HNO₃), and probe concentration (250 μmol L⁻¹) were studied in order to achieve highest signal attenuation. The signal suppression mechanism was investigated, indicating that it occurs due to the adsorption of atorvastatin and its oxidation products on the working electrode surface competing with the probe deposition. This suppression approach enhanced the analytical signal by a factor of 100 times when compared to the atorvastatin signal monitoring, leading the optimized method to a limit of quantification (LOQ) of 0.41 μmol L⁻¹ with the linear response up to 2.85 μmol L⁻¹. The repeatability was determined to be 2.95% (n = 10) and the method showed selectivity against other statins (rosuvastatin and pravastatin). As a proof of concept, atorvastatin was determined in a pharmaceutical formulation sample, with a satisfactory recovery of 100.3 ± 3.2%.

Keywords:

• Atorvastatin
• Pb2+ probe
• square-wave voltammetry (SWV)

Additional information

Funding

The authors are grateful to the Brazilian institutions Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for scholarships and sponsorships. R. Q.