Efficient and accessible detection of organophosphorus pesticides in food using Pr₆O₁₁/Zr-MOF nanozyme: Advancing food safety

The universality of detecting organophosphorus pesticides in vegetables and fruits is crucial for ensuring food safety; however, this remains a challenge. In this study, we successfully developed an efficient nanozyme for organophosphorus detection with easy-to-interpret visual results, using Zr-metal–organic framework (MOF) to anchor Pr₆O₁₁. The detection capability of Pr₆O₁₁, which arises from the polyvalent states of metal atomic orbitals, was significantly enhanced by Zr-MOF. This combination prevented Pr₆O₁₁ aggregation and enriched organophosphorus compounds in the environment through coordination, allowing the colorimetric method to achieve a limit of detection (LOD, signal-to-noise ratio (S/N) = 3) as low as 1.47 μg·mL⁻¹. Additionally, the method provides a visual and rapid result interpretation via red–green–blue (RGB) color analysis using a smartphone app, making it accessible for non-experts. To demonstrate its accessibility, organophosphorus residues in commercially available cucumbers, lettuce, and rapeseed were investigated, validating the method with a spiked recovery test. The recovery rates ranged from 95% to 105%, with a relative error of less than 5%. The reaction time of the method was as short as 40 min, confirming its reliability and accessibility. Therefore, the Pr₆O₁₁/Zr-MOF nanozyme, coupled with the smartphone app, offers a reliable organophosphorus detection method with significant implications for food safety.