Flow Injection Analysis System Coupled to Chronoamperometry and Boron-Doped Diamond Electrode for Determination of Synthetic Hormones 17α-Ethinylestradiol and Cyproterone Acetate

Abstract

Flow injection analysis with chronoamperometry detection using a cathodically pretreated boron-doped diamond electrode (CPT-BDDE) was employed to develop and optimize a novel method for the determination of the hormones 17-α-ethinylestradiol (EE2) and cyproterone acetate (CPA). The electrochemical properties of EE2 and CPA were evaluated by cyclic voltammetry and oxidation peaks were observed at 0.97 V and 1.60 V in 0.04 mol L−1 Britton-Robinson buffer (pH 2.0). Analytical curves were linear in the concentration range from 0.070 to 10.0 µmol L−1 for EE2 and 1.0 to 80.0 µmol L−1 for CPA with detection limits of 0.023 and 0.23 µmol L−1, respectively. The developed methods presented good precision and accuracy for EE2 and CPA quantification in commercial pharmaceutical samples. The obtained results were satisfactory and consistent compared with a reference high-performance liquid chromatography method at a confidence level of 95%. Furthermore, recovery studies carried out in synthetic urine and lake water show that these methods do not suffer any significant matrix interferences and are potentially applicable for the determination of these hormones in real samples. Thus, the developed procedure for EE2 and CPA determination are simple and fast, with an analytical frequency of ∼83 determinations per hour, and attractive for routine analysis.