ZrO₂@C-MOF-808: A carbonized MOF-Based nanocomposite for sensitive electrochemical detection of ulipristal acetate

To the best of our knowledge, this study presents the first electrochemical sensing platform for the selective determination of ulipristal acetate (UA), based on a ZrO₂@C-MOF-808 nanocomposite-modified glassy carbon electrode (GCE) for applications in biological and pharmaceutical samples. The ZrO₂@C-MOF-808 composite was synthesized through carbonization of MOF-808 at 800 °C under an Ar/H₂ atmosphere. Structural analyses using XRD, SEM, Raman spectroscopy, and XPS confirmed the formation of crystalline ZrO₂ nanoparticles uniformly embedded within a conductive carbon matrix. The electrochemical behavior of UA at the modified electrode was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimized conditions (0.1 M PBS, pH 6.0), the sensor exhibited a linear response in the range of 1.0-4.07 μM with a low detection limit of 0.02 μM. The proposed platform demonstrated excellent repeatability (RSD = 1.24%) and reproducibility (RSD = 1.04%), along with high selectivity toward UA in the presence of common interferents. The sensor was successfully applied to pharmaceutical formulations and biological samples, including human plasma and urine, achieving recovery values between 97.34% and 102.25%. In addition, the environmental sustainability of the developed method was assessed using the Greenness Evaluation Metric for Analytical Methods (GEMAM), confirming its green and resource-efficient analytical profile. These findings highlight the potential of the ZrO₂@C-MOF-808/GCE as a cost-effective and reliable platform for UA determination in pharmaceutical quality control and clinical analysis.