Sensing of mercury ion using light induced aqueous leaf extract mediated green synthesized silver nanoparticles of Cestrum nocturnum L.

In this study, a simple, one-pot, and eco-friendly biosynthesis of silver nanoparticles (AgNPs) was accomplished with the use of aqueous leaves extract of Cestrum nocturnum L.(AECN). Different techniques like ultraviolet-visible (UV-Vis) spectrophotometry, Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning area electron diffraction were used to investigate the optical, operational, and physical properties of the green synthesized AECN-AgNPs.The AECN-AgNPs were further used for the detection of Hg 2+ by UV-Vis and electrochemical methods. The disintegration of the AECN-AgNPs solution caused the formation of an Ag-Hg amalgam, which caused discoloration of the solution. Sensing performance for a variety of metals such as Na + , K + , Mg 2+ , Ca 2+ , Ni 2+ , Cu 2+ , Fe 3+ , Zn 2+ , Co 2+ , Cd 2+ , Pb 2+ , As 3+ , and Mn 2+ at 10-mM concentrations was measured in order to determine the selectivity of the sensor towards the Hg 2+ . For the electrochemical determination of 2 + Hg 2+  , AECN-AgNPs were immobilized on a glassy carbon (GC) electrode, and the resulting modified electrode (GC/AECN-AgNPs) was characterized by cyclic voltammetry. This phenomenon is advantageously used for the sensitive determination of trace level Hg 2+ . GC/AECN-AgNPs demonstrated a linear calibration range of 100 nM to 10 μM and a limit of detection of 21 nM for Hg 2+ determination.