Highly selective, rapid and simple colorimetric detection of Fe3+in fortified foods by L-Cysteine modified AuNP

Herein, we have developed a simple, stable and cost-effective L-cysteine modified caffeic acid mediated gold nanoparticles (Cys-Caf-AuNP) that showed promising application in detection of Fe3+. Cys-Caf-AuNP was characterized through different advanced analytical techniques which was further implemented in selective detection of Fe3+ in the range of 0.5–5 µM that exhibited LOD (Limit of Detection) of 0.22 µM. Optimization of pH and temperatures were done for conducting efficient detection of Fe3+. Smartphone integrated detection was also approached for detection of Fe3+. Practical reliability of Cys-Caf-AuNP in sensing of Fe3+ was checked carefully in iron fortified foods. The mechanism of selective sensing Fe3+ over Fe2+with Cys-Caf-AuNP was studied through DFT.