摘要The overuse of antibiotics has led to the severe contamination of water bodies,posing a considerable hazard to human health.Therefore,the development of an accurate and rapid point-of-care testing(POCT)platform for the quantitative detection of antibiotics is necessary.In this study,Cerium oxide(CeO2)and Ferrosoferric oxide(Fe3O4)nanoparticles were simultaneously encapsulated into N-doped nanofibrous carbon microspheres to form of a novel nanozyme(CeFe-NCMzyme)with a porous struc-ture,high surface area,and N-doped carbon material properties,leading to a considerable enhancement of the peroxidase(POD)-like activity compared with that of the CeO2 or Fe3O4 nanoparticles alone.The POD-like activity of CeFe-NCMzyme can be quenched using L-Cysteine(Cys)and subsequently restored by the addition of a quinolone antibiotic(norfloxacin,NOR).Therefore,CeFe-NCMzyme was used as a colorimetric sensor to detect NOR via an"On-Off"model of POD-like activity.The sensor possessed a wide linear range of 0.05-20.0 μM(R2=0.9910)with a detection limit of 35.70 nM.Furthermore,a smartphone-assisted POCT platform with CeFe-NCMzyme was fabricated for quantitative detection of NOR based on RGB analysis.With the use of the POCT platform,a linear range of 0.1-20.0 μM and a detection limit of 54.10 nM were obtained.The spiked recoveries in the water samples were ranged from 97.73％to 102.01％,and the sensor exhibited good accuracy and acceptable reliability.This study provides a portable POCT platform for the on-site and quantitative monitoring of quinolone antibiotics in real samples,particularly in resource-constrained settings.