Biogenic AgNPs for the Non-Cross-linking Detection of Aluminum in Aqueous Systems

Nanoparticle synthesis is one of the most innovative areas of the 21st century in which the implication of the experimental biogenesis process is significant. We report biogenesis of silver nanoparticles (AgNPs) using cinchona bark extract in which cinchona bark extract acts as a reducing agent and stabilizing agent and does not require additional reducing and stabilizing agent. The cinchona-silver nanoparticles (C-AgNPs) were monodispersed with a size of 3–4 nm, stable, highly selective, and used for non-cross-linking detection of aqueous Al3+ ion colorimetrically. C-AgNPs provide a good limit of detection (LOD) of 0.01 ppm for Al3+ that is well below the detection limit set by USEPA (50 ppm) and WHO (0.199 ppm) and is based on the deep yellow to brown color tuning of the C-AgNPs based detection system. The synthesis of C-AgNPs was optimized in terms of pH, concentration of extract, and the effect of temperature. Morphology and the size of AgNPs were characterized by HRTEM and DLS analysis. Thus, without an additional noxious agent and any labeling agent that is required for cross-linking, a simple, fast, and selective colorimetric method is proposed for ultrasensitive detection of health hazardous aluminum ions. Moreover, this non-toxic, biocompatible plant extract allows the successful detection of Al3+ ions in real water samples.