Nanomolar Level Acetaminophen Sensor Based on Novel Polypyrrole Hydrogel Derived N-doped Porous Carbon

This study develops a novel approach to morphology-controlled N-doped porous carbons (NPC) derived from supramolecular crosslinked polypyrrole hydrogel (PPy-gel) with tetra-functional tetrakis(4-carboxyphenyl)porphyrin as dopant and cross-linker. Both optimized PPy-gel and NPC realize acetaminophen determination at nanomolar level, displaying record-low respective detection limits of 3.0 and 1.0 nM (S/N=3). The optimized NPC demonstrates necklace-like structure with more edge pyridinic N, revealing better electronic conductivity and higher electrochemically active surface area, and consequently higher sensitivity and selectivity. Even in the presence of three interferences (ascorbic acid, dopamine and uric acid), NPC based electrochemical sensor also shows the ultra-low detection limit (1.2 nM). The promising application potential of the sensor is proved by the high consistence between measurements in pharmaceutical sample and established acetaminophen standard curve. Moreover, the determination results of acetaminophen in human urine sample obtained by this sensor were in a good agreement with the reference values assayed by HPLC.