Rapid detection of Pb2+ heavy metal ions using paper-based green synthesized silver nanoparticles colorimetric assays.

Herein we report the facile synthesis of silver nanoparticles (AgNPs) via the green synthesis method using mangosteen (Garcinia Mangostana L.) peels waste extract (MPE) as the bioreducing agent. The synthesized AgNPs were employed as the probe in the paper-based colorimetric detection of Pb²⁺. Initially, the MPE was prepared using a reflux system for a 3 h reaction, followed by mixing the AgNO₃ precursor and the prepared MPE, then left undisturbed for a 6 h reaction until a dark brown solution of AgNPs was obtained. The AgNPs showed a strong visible absorbance peak at 415 nm that indicated the AgNPs were successfully formed, whereas there was no peak observed at 415 m for the MPE. Further investigation, the IR spectra revealed that the OH-groups of flavonoids derivative in the MPE have a main role in the AgNPs formation, while the XRD pattern confirmed the prepared AgNPs have face center cubic structure with the crystalline size of 11.38 nm as well as the SEM characterization showed a spherical to triangle morphology of AgNPs. The paper-based-colorimetric performance evaluation showed a wide linearity range from 8 ppb to 100 ppm with a limit of detection (LOD) less than 12.50 ppm and high selectivity toward Pb²⁺ instead of Zn²⁺, Mg²⁺, Na⁺, and K⁺ at 30 min reaction, indicating the green synthesized AgNPs have the potential for probe in colorimetric sensing. [ABSTRACT FROM AUTHOR]