Naked eye sensing of melamine: aggregation induced recognition by sodium d-gluconate stabilised silver nanoparticles

Abstract

A highly selective, sensitive and low-cost colorimetric sensor for a biologically important analyte, namely melamine, is reported using sodium D-gluconate stabilised silver nanoparticles. Hydrogen bonding between sodium D-gluconate and melamine induces aggregation of silver nanoparticles with a consequent color change. The aggregation induced color change from yellow to red is monitored by UV-visible spectroscopy and the structure is confirmed by HRTEM. The selective sensing of melamine by sodium D-gluconate stabilised silver nanoparticles is also confirmed by competitive binding studies. The detection limit is found to be 5 × 10⁻⁷ M (0.06 ppm) and this melamine sensor also finds applications in real sample analysis.