Colorimetric detection of melamine using β-cyclodextrin-functionalized silver nanoparticles

Highly robust silver nanoparticles were developed and functionalized using a single reducing and functionalizing agent β-cyclodextrin, and the prepared silver nanoparticles were exploited as probes for the colorimetric sensing of melamine. The monodispersed and spherical-shaped silver nanoparticles were obtained with an average particle size of 10 nm, and the addition of melamine induced the aggregation of nanoparticles, as evidenced from the morphological characterizations. The toxic melamine was effectively sensed through the colorimetric response, owing to the host-guest inclusion of melamine into the hydrophobic cavities of β-cyclodextrin-functionalized silver nanoparticles. The influence of pH and time on the colorimetric detection of melamine has also been investigated in detail. Furthermore, the fabricated sensor exhibited a practical applicability in the quantification of melamine in pasteurized milk samples with the moderate recovery and relative standard deviation values. The environmentally benign one-pot synthesis of functionalized silver nanoparticles has not only provided fundamental knowledge on the development of functionalized nanostructures, but also has paved the way for the construction of simple and effective colorimetric probes for the detection of melamine.