Highly selective and effective environmental mercuric ion detection method based on starch modified Ag NPs in presence of glycine

摘要

The rapid colorimetric detection of mercury from environmental and biological samples raised the research for the development of a nanoparticles (NPs) based detection system. This investigation reports the colorimetric detection of mercuric ion from drinking water and industrial effluents using silver nanoparticles. Here, chemical reduction method was used to prepare starch stabilized Ag NPs. The particle synthesized was characterized by UV-visible spectrophotometer, particle size analyser, zeta sizer, TEM, EDX, XRD and FT-IR. The starch capped particle showed zeta potential of -34.33 +/- 3.0 mV. The particles were spherical shaped and showed the hydrodynamic diameter of 9 +/- 1.3 nm. In the presence of amino acid glycine, Ag NPs detect Hg(II) in nano-molar level. On interaction with Hg(II) at increasing concentrations, there was a colour gradient from yellow colour of NPs solution to colourless. Plot between absorbance at 416 nm and Hg(II) concentration at 20-100 nM showed good linearly under optimized condition. The LOD for the Hg(II) detection by the probe was determined to be 17 nM. The other metal ions presence in the analyze did not interfere for Hg(II) detection. The influence of environmental conditions such as pH, temperature and salinity on Hg(II) detection were studied. The probe was applied to quantify Hg(II) from Bhavani river and it was found to be 74 nM which was further confirmed with atomic absorption spectrophotometric analysis. Further, Hg(II) separation was done by bringing the solution pH to 11.0. The study suggest the easy and simple method for the quantitative and qualitative determination of Hg(II) from aqueous samples.