Cu-MOFs nanozyme with POD-like activity for the enrichment, identification, and intelligent colorimetric detection of omethoate

To effectively overcome the shortcomings of traditional chromatographic and enzymatic methods for detecting organophosphorus pesticides, Cu-MOFs with inherent peroxidase (POD)-like activity were constructed for direct colorimetric detection of omethoate (OMT). Benefiting from the mesoporous and benzene ring structure, Cu-MOFs demonstrated excellent OMT enrichment capability. OMT exhibited a pronounced inhibitory effect on the POD-like activity of Cu-MOFs whereas other pesticides showed negligible interference, demonstrating the specific identification of OMT by Cu-MOFs. Experimental data and theoretical calculations indicated that OMT effectively bond to Cu-MOFs through Cu 2+ coordination and ligand binding. Owning to its enrichment, identification and catalytic abilities, OMT detection was achieved and the limit of detection (LOD) was 16 μg L −1 . Furthermore, a smartphone-assisted portable detection was established with a LOD of 79 μg L −1 . Validation experiments of cabbage samples confirmed its’ reliability for practical applications. Our system integrated the enrichment, identification, and detection of OMT within a single system, improving both sensitivity and operational convenience.