Developing high-performance, low-cost electrochemical sensors for therapeutic drug monitoring remains challenging. This work reports a novel strategy for one-step synthesis of Fe/FeNₓ@C nanoclusters with a metastable amorphous-crystalline carbon coupling interface, utilizing the transient high-temperature quenching effect of direct-current arc plasma. This unique structure (FNFC) synergistically combines high conductivity, abundant defects, and strong metal-carrier interactions. The FNFC-based sensor demonstrates outstanding performance for isoniazid: a linear range spanning 0.05–200 μM (covering clinically relevant concentrations), a detection limit as low as 0.0160 μM, and a sensitivity of 0.775 μA μM −1 cm −2 , outperforming most recently reported sensors. Additionally, the sensor demonstrated good recovery rates in spiked rat serum, providing preliminary evidence of its potential for detection in complex biological matrices. Mechanistic studies indicate that its performance stems from the synergy between the molecular enrichment pathways provided by amorphous carbon and the optimized electron transfer at the crystalline carbon/FeNₓ interface. A novel composite material FeN 0.0499 -Fe@C (FNFC) has been successfully constructed via a facile direct-current arc plasma method, which presents a nanocluster consisting of small particles with a nanocore-shell structure embedded in amorphous carbon. Based on this composite material, an electrochemical sensor for the detection of isoniazid has been constructed with excellent detection performance. • FNFC has been synthesized by a facile direct-current arc plasma method. • FNFC electrochemical sensors exhibit low detection limits for isoniazid detection. • Multiple interfaces and coupling effect promote sensitive detection of isoniazid.
Dong et al. (Sun,) studied this question.