Development of environmentally friendly voltammetric methods for the individual and simultaneous determination of antihypertensives: Validation and application

Abstract

In this study, voltammetric methods were developed and validated for the individual determination of lisinopril (LSNP) and its association with hydrochlorothiazide (HCTZ) employing a cathodically pretreated boron-doped diamond (CP-BDD) electrode. The studies of the experimental and instrumental parameters that affect the performance of both methods were carefully carried out by optimizing each parameter. The methods were validated by evaluating the figures of merits recommended by the validation guidelines. The method for the individual determination of LSNP presented a linear working range between 9.99 and 196.01 nmol L−1, with a limit of detection of 3.05 nmol L−1 by differential pulse voltammetry in BR buffer solution (pH 2.0). Simultaneous analytical curves over the concentration ranges of 0.40–3.99 and 0.050–1.045 μmol L−1 for HCTZ and LSNP, respectively, were obtained by square-wave voltammetry in Britton-Robinson buffer solution (pH 3.0). The limit of detection values calculated were 0.052 μmol L−1 and 0.020 μmol L−1, respectively for HCTZ and LSNP. The sensitivity observed for individual analytical curves of HCTZ and LSNP was statistically equal to that obtained for the simultaneous analytical curves at the 95 % confidence level. The developed methods were applied to determine these drugs in environmental, biological, and pharmaceutical samples, with satisfactory results. The method's greenness was assessed demonstrating that both validated methods constitute a greener alternative to conventional analytical methods reported in the literature.