An ultrafine ZnO/ZnNi2O4@porous carbon@covalent-organic framework for electrochemical detection of paracetamol and tert-butyl hydroquinone

An electrochemical sensor based on ultrafine ZnO/ZnNi2O4 @porous [email protected] framework (COF) was constructed for the detection of paracetamol (PA) and tert-butylhydroquinone (TBHQ). First, Ni-doped zeolite imidazolium framework-8 (ZIF-8) was used as pyrolysis precursor to obtain porous carbon-encapsulated ultrafine ZnO/ZnNi2O4 (ZnO/ZnNi2O4 @porous carbon) with a specific surface area of about 1130 m2 g−1. Then, COFTM was grew on ZnO/ZnNi2O4 @porous carbon by amine-aldehyde condensation reaction between 3,5-triformylphloroglucinol (TPF) and 1,3,4,6,7,9,9b-heptaazaphenalene-2,5,8-triamine (ML) around the ZnO/ZnNi2O4 @porous carbon. The ultrafine ZnO/ZnNi2O4 nanoparticles were evenly dispersed in porous carbon. The N,O-rich COFTM was used as the outer shell to enhance the stability of ZnO/ZnNi2O4 @porous carbon and simultaneously could enrich the PA/TBHQ and improve selectivity of sensor. The electrochemical sensor based on the core-shell structured nanocomposite exhibited wide linear ranges of 48.5 nM-130 μM and 47.85 nM-130 μM for detecting PA and TBHQ. The PA and TBHQ sensor also showed good stability, selectivity and sensitivity. This work not only provides a new method for the detection of drug molecules and additives in food but also gives an idea to improve the selectivity and stability of electrochemical sensor.