A rapid colorimetric method using cysteine-modified silver nanoparticles (Cys-AgNPs) is applied for the detection of 3-monochloropropane-1,2-diol (3-MCPD). Indeed, in the presence of 3-MCPD, the color of Cys-AgNPs solution changes from yellow to pink within five minutes at 100 °C and pH 9.3. This change is mainly attributed to the ability of amino group of cysteine to react with 3-MCPD to form N-(2,3-dihydroxypropyl)-amino acid grafted on AgNPs (3-MCPD-Cys-AgNPs) in alkaline medium. This color change makes 3-MCPD to be clearly detectable by unassisted visual means even at 0.1 μg⋅mL-1. Besides, using UV-Vis spectroscopic technique, a linear range from 0.1 μg⋅mL-1 to 1.25 μg⋅mL-1 for 3-MCPD detection is obtained, with a calculated detection limit of 0.084 μg⋅mL-1. These results suggest that this sensing technique is sensitive to 3-MCPD and may have a substantial application in the rapid detection of food contaminants particularly, where quality and safety of food products are paramount concern.
Keywords: 3-Monochloropropane-1,2-diol; Colorimetric detection; Cys-AgNPs; Smoked fish; Unassisted visual detection.
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