Sensitive Homogeneous Electrochemical Detection of Organophosphorus Pesticides by UiO-66-NH ₂ Embedded with a Ruthenium-tris(2,2′-bipyridyl)(II) Nanozyme

This study prepared UiO-66-NH₂ MOFs embedded with Ru-tris(2,2'-bipyridyl)(II) hybrids as a nanozyme (designated as Ru/UiO-66-NH₂) to propose a bioenzyme-free homogeneous electrochemical (HEC) sensing strategy for detecting organophosphorus pesticides (OPs). Experimental investigation coupled with density functional theory calculation demonstrated that the Ru incorporation significantly amplifies the peroxidase-like (POD-like) activity of UiO-66-NH₂ MOFs and that the Ru/UiO-66-NH₂ nanozyme exhibits selective responsiveness to coordinate with the OP molecules. Upon OP exposure, the specifical coordination between OPs and MOF structure effectively inhibits the nanozyme's activity. Utilizing <i>o</i>-phenylenediamine as the catalytic substrate and glyphosate as a model of OPs, the optimized HEC sensor achieves an extensive linear detection range (0.5-10,000 ng/mL) and a low detection limit of 0.13 ng/mL as well as satisfactory recoveries in the real samples of tomato extract and water. It is expected that this innovative bioenzyme-free HEC sensing strategy represents a promising advancement for practical OP residue analysis with potential applications in various fields.