Supramolecular phenolic network-engineered C-CeO2 nanofibers for simultaneous determination of isoniazid and hydrazine in biological fluids

Electrochemical sensing provides a powerful technological means for the therapeutic drug monitoring of drug-resistant tuberculosis but requires a functionalized electrode to capture the analytes and catalyze their redox reactions. Herein, we construct a nickel-tannic acid supramolecular network (Ni-TA) on the surface of electrospun-derived C-CeO2 nanofiber for the sensitive and simultaneous detection of isoniazid (INZ) and hydrazine (HYD). Mechanistic investigations demonstrate that Ni-TA is electronegative and hydrophilic, thus facilitating an efficient mass and electron transfer. Ni-TA/C-CeO2 has higher adsorption rate constants (0.091 g mg–1 h–1 for INZ, and 0.062 g mg–1 h–1 for HYD) than native C-CeO2 (0.075 g mg–1 h–1 for INZ, and 0.047 g mg–1 h–1 for HYD). Moreover, Ni-TA/C-CeO2 (56 Ω) has lower charge transfer resistances than C-CeO2 (417 Ω). Ni-TA/C-CeO2 performs low detection limits and wide linearity ranges for INZ (0.012 μmol/L and 0.1-400 μmol/L, respectively) and HYD (0.008 μmol/L and 0.015-1420 μmol/L, respectively), coupled with high selectivity, cycle stability and reproducibility. This research demonstrated the promising applications of Ni-TA/C-CeO2 by analyzing human-collected plasma and urine samples.