Bioenzyme-free dual-mode sensing for organophosphorus pesticides based on UiO-66-NH2 MOFs encapsulated tris(2,2′-bipyridyl) ruthenium(II)

Herein, we proposed a novel bioenzyme-free dual-mode sensing strategy for the rapid and accurate monitoring of organophosphorus pesticides (OPs) by preparing tris(2,2′-bipyridyl) ruthenium(II) (Ru(bpy) 3 2+ ) encapsulated with UiO-66-NH 2 MOFs as nanozyme (Ru@Zr-MOFs). The as-prepared Ru@Zr-MOFs nanozyme not only exhibits superior peroxidase-like activity which can catalyze O-phenylenediamine (OPD) oxidation to generate yellow 2,3-diaminophenazinc, but also exhibits dual-fluorescence feature (at 442 and 612 nm respectively) and specific interaction capacity with OPs. However, in the existence of OPs, the peroxidase-like activity of Ru@Zr-MOFs nanozyme is restricted and the oxidation process of OPD is stopped; meanwhile, the fluorescence of Ru@Zr-MOFs at 442 nm increases rapidly (< 10 s) while that at 612 nm is apathetic, thus a colorimetric and ratiometric fluorescent sensing strategy was first designed to detect OPs by using glyphosate (Gly) as a typical model of OPs. Then, in consideration of the benefits of smartphone which can make the sensing process more convenient, stable, rapid and sensitive feedback, a smartphone coupled with hydrogel detection platform was proposed also for OPs determination. In addition, the designed sensing strategy offers superior selectivity , stability and real application capabilities. It’s thus expected the as-designed Ru@Zr-MOFs nanozyme based dual-mode sensing strategy possesses important real application for the low-cost, rapid, sensitive and accurate determination of OPs.