LAUSR

Abstract The surface modification of silver nanoparticles (AgNPs) with natural products could be environmentally friendly method of manufacturing provided that their inherent properties could be substantiated. Therefore, AgNPs were synthesized from AgNO3 using β-Cyclodextrin and seed extracts from Apple (Ap-AgNPs) and Nigella Sativa species (N-AgNPs). AgNPs thus prepared were incorporated as a colorimetric sensor for determining HgII ions and proved to be both selective and adequately sensitive in detecting mercuric ions. These nanoparticles are found to show a limit of detection (LOD) of 29.0 nM and 58.0 nM for Ap-AgNPs and N-AgNPs, respectively. The results demonstrate the higher sensitivity of Ap-AgNPs over N-AgNPs with maximum absorption causing a color shift to blue due to HgII ions and the resulted color change from yellow to pale yellow, even colorless upon addition of HgII in AgNPs solutions. The results validate the applicability of nanoparticles as a sensor with the potential for rapid and on-site detection of HgII ions.