Visual Quantification of Melamine Using Citrate-Capped Gold Nanoparticles

摘要

Du to its high nitrogen content and low cost, melamine, a widely used material in plastics industry, has been illegally added to food products to boost apparent protein content. We’ve previously developed a colorimetric method to detect melamine. This method utilizes the melamine-concentration dependent gradual color shift of gold nanoparticles (AuNPs) and an absorbance reader is usually required for reliable quantification of melamine. Herein, we present a novel strategy for reliable visual quantification of melamine without any equipment. First of all, we further explored the mechanism of the melamineinduced AuNP aggregation with various experimental techniqus. Secondly, based on the findings from the mechanism studies, we’ve developed and demonstrated a critical coagulation concentration (CCC)-based salt titration as a reliable means to visually quantify the melamine. This has allowed us to accurately quantify melamine at a level as low as 30 ppb without any equipment.