Sensitive and specific colorimetric detection of glyphosate utilizing laccase-mimicking activity of copper-based metal-organic framework.

Glyphosate (Gly), a widely used potent herbicide worldwide, possess potential harm to human health and environment due to accumulation in water and soil. Hence, there is a pressing need to realize the simple and precise detection of Gly to ensure human health and environmental safety. Although various nanozyme-based detection methods have been developed for Gly, they frequently require additional enzymes and hydrogen peroxide (H₂O₂). H₂O₂ not only exhibits certain toxicity but is also prone to decomposition, resulting in poor accuracy and reproducibility. In this study, we report the synthesis of nanoscale copper-based metal-organic framework (Cu-MOF) through a facile ultrasound method, and the resulting Cu-MOF demonstrate excellent laccase-mimicking activity. Our Cu-MOF nanozyme can catalyze the conversion of substrates into chromogenic products without the need for H₂O₂, offering a simple and mild operational approach. The presence of Gly significantly inhibits the catalytic activity of the Cu-MOF, hindering the chromogenic reaction between 2,4-dichlorophenol (2,4-DP) and 4-aminoantipyrine (4-AP). We propose a detection method for Gly that is repeatable, reliable, highly selective, and cost-effective, eliminating the need for additional H₂O₂, or bioenzymes. This facile strategy paves a new path for the applications of laccase-mimicking nanozyme in environmental monitoring.