Ultra-sensitive detection of mercury(II) ions in water sample using gold nanoparticles synthesized by Trichoderma harzianum and their mechanistic approach.

The present study demonstrates a simple, cost effective and selective method for colorimetric detection of mercury(II) ions using gold nanoparticles (AuNPs) synthesized by non-pathogenic and agriculturally considerable fungal biomass of Trichoderma harzianum ( T. harzianum ). The synthesized nanoparticles were characterized by UV–vis spectroscopy (UV–vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The as-synthesized AuNPs were used further for the selective optical detection of Hg 2+ ions. The color of AuNPs solution changes in the presence of Hg 2+ ions and also a substantial change in the surface plasmon resonance (SPR) of nanoparticles was observed even at minute concentration of Hg 2+ ions. The sensitivity and selectivity of AuNPs towards Hg 2+ ions was also analyzed in the presence of Pb 2+ , Zn 2+ , Cd 2+ , Fe 3+ , Ni 2+ , Ca 2+ , Mn 2+ , Al 3+ , Co 2+ and Na + ions. The mechanism of colorimetric detection of Hg 2+ ions was also discussed along with diagrammatic representation. [ABSTRACT FROM AUTHOR]