Colorimetric Sensing of Hg2+ and Fe3+ Ions in aqueous solution using Green Synthesized Silver Nanoparticles

Life Sciences-Chemistry for better environment

Abstract

Plant  extracts  have  a  very  important  role  for  the  synthesis  of  different  nanoparticles  due  to  its  reducing capability,  availability  and  nontoxicity.  Biosynthesized  silver  nanoparticles  were  investigated  for  colorimetric  sensing  of metal ions at different concentrations. Aqueous leaf extract of Plumeria alba was used as bio reduction to synthesize stable Silver  nanoparticles  (AgNPs).  A  possible  interaction  between  AgNPs  and  metal  ions  at  different  concentrations  was proposed on the basis of  UV-Vis  spectral  analysis.  The  produced silver nanoparticles were characterised by  different technique which includes UV–vis spectroscopy and transmission electron microscopy (TEM). The intensity of the localized surface plasmon absorption band at 438 nm in UV-visible spectrum confirmed the presence of silver nanoparticles. TEM analysis showed the spherical and irregular particles shape and size of nanoparticles ranging from 20 to 100 nm. Metal ion sensing properties of these AgNPs in aqueous solution has been explored. In the detection of different metal ions using these green synthesized AgNPs, the promising  colorimetric  response was observed with naked eyes and spectroscopic changes  were  examined  by  using  a  UV-Visible  spectrophotometer.  The  colorimetric  sensor  studies  showed  selective sensing  of  Fe3+   and  potentially  hazardous  Hg2+   ions  in  aqueous  medium  with  a  limit  of  detection  of  about  0.2  mM concentrations.  This  method  may  be  applied  as  low  cost  and  high  potential  colorimetric  sensor  for  the  selective recognition and monitoring of Hg2+  and Fe3+  ions in biological, pharmaceutical samples as well as in water.