Selective dual-mode detection of glyphosate facilitated by iron organic frameworks nanozymes

To satisfy the public's urgent demand for food safety and protect the ecological environment, sensitive detection of glyphosate holds paramount importance. Here, we discovered that glyphosate can engage in specific interactions with iron organic frameworks (Fe-MOFs) nanozymes, enabling a selective detection of glyphosate. Based on this principle, an innovative colorimetric and fluorescent dual-mode detection approach was devised. Specifically, Fe-MOFs were synthesized at room temperature, exhibiting remarkable peroxidase-mimic activity. These nanozymes catalyze the conversion of colorless and fluorescent 3,3′,5,5′-Tetramethylbenzidine (TMB) into blue oxidized and nonfluorescent TMB (oxTMB) in the presence of H2O2. However, the introduction of glyphosate disrupts this process by interacting with Fe-MOFs, significantly inhibiting the catalytic activity of Fe-MOFs through both physical (electrostatic and hydrogen bonding) and chemical interactions. This suppression further hindered the conversion of TMB to oxTMB, resulting in a reduction in absorbance and a corresponding enhancement in fluorescence. The method offers a colorimetric and fluorescence dual-mode detection capability with enhanced applicability. Notably, our approach avoids complex material modifications and is more stable and cost-effective than the traditional enzyme inhibition methods. This innovative detection technique holds immense potential for practical applications and provides a fresh perspective for the detection of pesticide residues.