Accurate electrochemical paracetamol sensor for drug control through catalytic roles of single Fe atoms

Abstract Inappropriate use of paracetamol (PA) can induce serious liver injury, and developing accurate PA detecting methods holds great importance in the fields of drug quality control and therapeutic drug monitoring. In this work, a novel electrochemical sensor for detecting PA was successfully fabricated based on iron single atoms distributed on multiwall carbon nanotubes (Fe/MWCNTs) that were prepared through the Lewis acid doping strategy. MWCNTs wrapped by polyaniline‐derived N‐doped carbon not only provide the anchoring sites for Fe, but also endow the catalyst with high conductivity and mass transfer ability. Theoretical calculation results reveal that atomically dispersed Fe sites hold good catalytic activity toward PA oxidation reaction, because of easier OH absorption at the first step and more facile occurrence of the key transformation from OH* + PA into H 2 O* + PA_H, during which electrons transferred from PA to catalysts, thereby facilitating the dissociation of N–H bond and the oxidation of PA. The Fe/MWCNTs sensor showed excellent PA detecting performance, delivering a low detection limit of 0.14 μM in wide ranges of 0.5–100 μM and 100–500 μM. Without any pretreatments, the built sensor can directly and accurately detect PA in several complex commercial pharmaceutical formulations and spiked human urine samples with satisfactory recoveries from 96.98% to 107.59%, thereby fully demonstrating its practical application prospects.