Biologically synthesized silver nanoparticle-based colorimetric sensor for the selective detection of Zn2+†
A simple, selective and cost effective colorimetric sensor has been investigated for the detection of Zn2+ using biologically synthesized silver nanoparticles (AgNPs). The AgNPs were prepared from the leaf extract of Amomum subulatum via two different procedures i.e., at room temperature and by a heat treatment procedure. The AgNPs prepared through the heat treatment procedure exhibited efficient results. The as synthesized AgNPs were studied by simple UV-vis spectroscopy which showed an intense absorption band at 425 nm which was further confirmed by FT-IR and SEM analysis. The synthesized AgNPs exhibited a good colorimetric sensing property towards Zn2+ by changing the color of the solution from yellowish-brown to colorless accompanying a decrease in absorption intensity. The proposed detection mechanism of the sensor has been discussed. The sensor showed an excellent linear response towards Zn2+ in the concentration range from 1 × 10−5 to 8 × 10−5 M with a correlation coefficient (R2) of 0.996. The detection limit of the method was found to be 3.5 × 10−6 M. There was no interference effect observed for Zn2+ detection in the presence of other heavy metal ions. The proposed sensor was successfully applied for the detection of Zn2+ in drinking water samples.