Ultrasensitive tadalafil detection with eco-friendly CeO2/Al-pillared clay incorporated pencil graphite paste electrode

In this study, we have constructed a novel voltammetric sensor based on montmorillonite clay (MMT) incorporated with CeO₂ nanoparticles using a composite graphite paste electrode as a cross linker (MMT-CeO₂NPs/GPG-PE) for the trace determination of tadalafil (TAD) drug. The characterization of CeO₂ nanoparticles has been conducted using various analytical techniques, including X-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. The morphology of the composite of CPG and MMT-CeO₂NPs/CPG was elucidated through scanning electron microscopy (SEM). The newly developed sensor (MMT-CeO₂NPs/CPG-PE) exhibited remarkable efficiency towards TAD oxidation using adsorptive stripping square-wave voltammetry (AdS-SWV) in Mcllvaine buffer solution (pH 8.0). A highly selective and sensitive method for TAD detection has been successfully applied based on MMT-CeO₂NPs/CPG-PE, showing two different linear concentration ranges of 0.005−0.1 and 0.1–9.9 µM. The LOD and LOQ were determined to be 1.97 × 10⁻¹⁰ and 6.57 × 10⁻¹⁰ M, respectively, with a sensitivity of 3916 µA µM⁻¹ cm⁻². Interestingly, the sensing electrode exhibited excellent reproducibility, reusability, and stability even after 30 days. Moreover, the newly developed nano-sensor (MMT-CeO₂NPs/CPG-PE) has been effectively utilized for the accurate detection of TAD in pharmaceutical formulations and spiked human blood serum and urine samples, demonstrating no interference from other substances.