In this study, a facile and green synthesis approach was employed to prepare calcium oxide nanoparticles (CaO NPs) using Cyperus plant extract as a natural and eco-friendly reducing and stabilizing agent. The synthesized CaO NPs were incorporated as a membrane modifier in a potentiometric sensor for the enhanced determination of the antihistamine drug pseudoephedrine hydrochloride (PSDO). Two sensors were fabricated: a conventional sensor based on a PSDO–phosphotungstic acid (PTA)–tributyl phosphate (TBP) membrane and a CaO nanoparticle–modified sensor (PSDO–PTA–TBP–CaO NPs). The modified sensor exhibited a broader linear concentration range (1.0 × 10⁻²–1.0 × 10⁻⁸ mol·L⁻¹) compared to the conventional sensor (1.0 × 10⁻²–1.0 × 10⁻⁶ mol·L⁻¹), along with an improved Nernstian slope of 58.03 mV·decade⁻¹ compared with 54.00 mV·decade⁻¹ obtained for the conventional sensor, as well as excellent correlation coefficients (R² = 0.9997 and 0.9994, respectively). Moreover, the detection limit was markedly improved from 2.18 × 10⁻⁷ mol·L⁻¹ for the conventional sensor to 4.6 × 10⁻⁹ mol·L⁻¹ for the CaO NP–modified sensor. The proposed sensor demonstrated superior sensitivity, selectivity, and rapid response toward PSDO determination in both pure and pharmaceutical formulations. These findings highlight the significant role of green-synthesized CaO nanoparticles in enhancing potentiometric sensor performance and further support their potential application in sustainable electrochemical sensing systems.
Yassin et al. (Mon,) studied this question.