Co-based metal–organic frameworks synthesized from poly(ethylene terephthalate) waste plastics for rapid detection of p-phenylenediamine

-phenylenediamine (PPD). Based on the solvent-controlled sensing performance of CoMOFs, a highly sensitive and rapid detection method has been developed for PPD, with a linear range from 0.05 to 8.0 μM. The detection limit was 45 nM, and the practical application in hair dye samples was successfully demonstrated.