First report on electrochemical sensing of ulipristal acetate in pharmaceutical formulations and biological fluids using reduced graphene oxide–CuO nanohybrid based sensors

The present study illustrated for the first time the construction, characterization, and electroanalytical validation of reduced graphene oxide-copper oxide nanoparticles based screen-printed carbon electrodes (rGO-CuONPs-SPCEs) for sensitive differential pulse voltammetric quantification of ulipristal acetate (ULP) in pharmaceutical and biological samples. The rGO/CuONPs ratio within the nanohybrid was optimized with comprehensive characterization of the morphology and the electroanalytical features of the electrode surface. The fabricated sensors with the optimal composition exhibited enhanced performance towards the oxidation of ULP molecule at 0.72 V with a diffusion-controlled mechanism. Deep and comprehensive molecular orbital and electroanalytical studies sustained oxidation of the terminal nitrogen atom (N2) with the transfer of two electrons/one proton. The illustrated calibration graphs were linear within the ULP concentration ranged from 0.010 to 5.04 µgmL−1, with LOD value of 0.003 µgmL−1. The developed sensors showed prolonged lifetime, high mechanical stability, and measurement reproducibility. The presented voltammetric procedure has been introduced for sensitive monitoring of ULP residues in biological and pharmaceutical samples. The outcomes were contrasted with the previously reported ULP analytical methods.