Rapid fluorimetric determination of glyphosate in beer and fruit juices using a chitosan-coated magnetic-fluorescent...

Glyphosate is the most widely used herbicide in the world and is frequently detected in food. Magnetic and fluorescent molecularly imprinted polymers (MFMIP) were developed for rapid, selective GLY detection in food matrices. Two systems, MFMIP and chitosan-coated MFMIP-CS, were synthesised and characterised by FTIR, thermogravimetry, zeta potential, N₂ adsorption-desorption isotherms, and electron microscopy. Chitosan coating was introduced to mitigate matrix effects and surface fouling, enabling reliable fluorescence readout directly in complex beverages. The MFMIP-CS sensor showed matrix-specific nominal interaction times of 1 min for beer, 2 min for strawberry juice, 3 min for orange juice, and 4 min for grape juice; detection limits of 0.0016-0.0066 mg L^-1; linearity between 0.005 and 0.50 mg L^-1; recoveries of 86.96%-106.90%; and intraday precision ≤5.74%. GLY residues were found in beer, grape, and strawberry juices. The proposed method combines sensitivity, speed, and environmental sustainability, offering a promising alternative for routine glyphosate monitoring in food samples.