Development of a Zr/Fe-MIL nanozyme sensor integrated with a user-friendly colorimetric device for glyphosate monitoring

Timely and efficient analysis of glyphosate (GLP) in agriculture and environment is critical for food safety and public health. Herein, a paper-based enzyme sensor integrated with a portable device for GLP monitoring was developed. First, zirconium ions were doped into a typical iron-based MOF (Fe-MIL) <i>via</i> a simple solvothermal method, yielding a Zr/Fe-MIL composite that exhibits remarkable peroxidase-like activity. Zr/Fe-MIL had the capability to sensitively detect GLP, and the sensing mechanism was attributed to the coordination, hydrogen bonding and electrostatic interactions between Zr/Fe-MIL and GLP. Subsequently, a test strip combined with a portable device was designed to integrate automatic extraction, collection, and processing of colorimetric signals, enabling rapid signal analysis and direct concentration output. This system achieved linear ranges of 0.1-1 μg mL^-1 and 1-10 μg mL^-1, with a low limit of detection (LOD) of 29.1 ng mL^-1. The proposed strategy could also be applied to water and food samples (sorghum and soybean) with the recovery rates of 98.53-112.94%. This work provides an effective strategy for the development of portable and user-friendly methods for monitoring GLP.