Design and Development of Silver Nano-material Based Colorimetric Sensor for Detection of Melamine in Milk

Milk is a vital source of nutrients for individuals of all age groups. However, the adulteration of milk, particularly with melamine, poses serious health concerns. Melamine, a nitrogen-rich industrial compound, is illicitly added to falsely elevate protein content, leading to adverse effects such as renal failure. Although conventional detection methods like high-performance liquid chromatography (HPLC) and mass spectrometry are reliable, they are often costly and unsuitable for real-time field use. This paper presents a silver nanoparticle (AgNP)-based colorimetric sensor for the detection of melamine in milk. The presence of melamine induces aggregation of citrate-capped silver nanoparticles, resulting in a distinct colour change that is observable by the naked eye and verifiable using UV-Visible spectrophotometry. A detection limit of 0.1 ppm is achieved, meeting relevant regulatory standards and offering a practical approach for food safety monitoring.