Cost-effective carbon paper strip electrode modified with ZnO/Nb2CTx composite for sensitive electrochemical detection of epinephrine

초록

Accurate and rapid quantification of epinephrine (EPI) is essential for clinical management, yet conventional methods are costly and complex. Herein, a cost-effective carbon paper strip electrode modified with a ZnO/Nb2CTx composite was developed for sensitive electrochemical detection of EPI. Nb2CTx MXene was synthesized via HF etching of Nb2AlC, while ZnO nanoflakes were prepared through a sol-gel/hydrothermal route, and they were integrated at an optimized ratio. The hybrid electrode combined the high conductivity and oxygen-rich surface of Nb2CTx with good electrocatalytic activity of ZnO, enabling enhanced charge transfer and strong surface-analyte interaction. A Schottky barrier at the interface further accelerated EPI redox kinetics. The sensor exhibited linear behaviors in both nanomolar (100-900 nM) and micromolar (1-100 mu M) ranges with a low detection limit of 45.4 nM. It also showed excellent EPI selectivity, reproducibility (RSD < 1%), and stability (>95% retention after 7 days). Practical applicability was further demonstrated by accurate recovery (97.7-100.5%) in bovine serum albumin and human serum, highlighting its potential for low-cost clinical diagnostics and real-time monitoring.

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