An upconverted nanoparticle-porphyrin metal-organic framework platform for near-infrared detection of nitenpyram

A ratiometric nitenpyram (NIT) upconversion luminescence sensor UCNPs-PMOF was fabricated from a metal-porphyrin organic framework (PMOF) and pretreated UCNPs. The reaction between NIT and the PMOF releases the H₂TCPP (5,10,15,20-tetracarboxyl phenyl) porphyrin ligand, which enhances the absorption of the system at 650 nm, and reduces the upconversion emission intensity of the sensor at 654 nm through a luminescence resonance energy transfer (LRET) mechanism, thus achieving the quantitative detection of NIT. The detection limit was 0.21 μM. Meanwhile, the emission peak of UCNPs-PMOF at 801 nm does not change with the concentration of NIT, and the emission intensity ratio (I_{654 nm}/I_{801 nm}) is used to achieve the ratiometric luminescence detection of NIT, and the detection limit is 0.22 μM. UCNPs-PMOF has good selectivity and anti-interference to NIT. In addition, it has a good recovery rate in actual sample detection, which indicates that it has high practicability and reliability in NIT detection.