A liquid colorimetric chemosensor for ultrasensitive detection of glyphosate residues in vegetables using a metal oxide with intrinsic peroxidase catalytic activity

ABSTRACT

The control of pesticide residues in food is of increasing importance nowadays due to the over-use and misapplication of herbicides in agricultural production. However, the current colorimetric method for rapid detection of glyphosate still faces many challenges like the low sensitivity and stability. Herein, a simple and ultrasensitive liquid colorimetric chemosensor for glyphosate detection was successfully constructed. Glyphosate pesticide can interact with metallic oxidelike porous Co₃O₄ nanodisc, and inhibit its inherent peroxidase-mimicking activity, making the colour of the solution change from blue to light blue or even colourless. The colour variation of the colorimetric chemosensor enables us to easily distinguish in less than 20 min even by the naked eye whether glyphosate exceeds the allowable level. The limit of detection (LOD) of the chemosensor for glyphosate was calculated as low as 2.37 μg·L⁻¹, and the chemosensor displays excellent selectivity against other competitive pesticides and metal ions. Further studies have also validated the applicability of the colorimetric chemosensor in actual samples like tomato, cucumber and cabbage, indicating that the proposed strategy may have promising application prospects for detecting glyphosate residues in agricultural products.

GRAPHICAL ABSTRACT

KEYWORDS:

• Pesticide
• foods
• nanozyme
• rapid detection
• visual analysis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China [32160603, 31760486, 31801509], The Guizhou Provincial Science and Technology Foundation (ZK[2021]Key Project 037), The Guizhou Provincial Outstanding Young Science and Technology Talent Project ([2021]5628), The Science and Technology Platform and Talent Team Project of Guizhou Province ([2018]5251), The Talent Base of Fermentation Engineering and Liquor Making in Guizhou Province ([2018]3), and The Open Foundation of Key Laboratory of Wuliangye-flavor Liquor Solid-state Fermentation [2021JJ015], China National Light Industry.