Nano Enabled Plasmonic Strips For Colorimetric Detection Of Food Adulterants

Paper‐based analytical devices constitute a remarkable platform for low‐cost and point‐of‐care application with minimal external resources. The present work aims at the development of gold nanoparticles (AuNPs) based plasmonic substrates for food sensor application. AuNPs were synthesized by using redox method with dual reducing agents (tannic acid and citrate ions). Physicochemical and sensing characteristics were determined by various spectroscopic and microscopic techniques. The sensing characteristic was evaluated using melamine (MA) as representative analyte (food adulterants). HR‐TEM images imply that the synthesized AuNPs was spherically‐shaped with an average dimension of 5 nm. After the interaction of MA with AuNPs, the size of the NPs changed from 5 to 8.9 nm due to aggregation. The interaction of MA with AuNPs has been carried out in the solution phase as well as in the strip phase by visual and spectroscopic techniques. The concentration dependent color variation was observed with a limit of detection 5×10−5 M in the solution phase. This sensor probe is highly specific for MA and did not show any visible color variation with other adulterants. The sensor system is simple, reproducible and highly promising for rapid and low‐cost sensing of MA in food samples. Development of gold nanoparticles by chemical reaction method using dual reducing agents. AuNPs were characterized by various spectroscopic and microscopic techniques. The sensing characteristics were evaluated in solution as well as in the strip format under the optimized conditions. Further, the real sample analysis was carried out with raw milk.