Synthesis of Starch-Stabilized Ag Nanoparticles and Hg2+Recognition in Aqueous Media

Abstract

The starch-stabilized Ag nanoparticles were successfully synthesized via a reduction approach and characterized with SPR UV/Vis spectroscopy, TEM, and HRTEM. By utilizing the redox reaction between Ag nanoparticles and Hg²⁺, and the resulted decrease in UV/Vis signal, we develop a colorimetric method for detection of Hg²⁺ion. A linear relationship stands between the absorbance intensity of the Ag nanoparticles and the concentration of Hg²⁺ion over the range from 10 ppb to 1 ppm at the absorption of 390 nm. The detection limit for Hg²⁺ions in homogeneous aqueous solutions is estimated to be ~5 ppb. This system shows excellent selectivity for Hg²⁺over other metal ions including Na⁺, K⁺, Ba²⁺, Mg²⁺, Ca²⁺, Fe³⁺, and Cd²⁺. The results shown herein have potential implications in the development of new colorimetric sensors for easy and selective detection and monitoring of mercuric ions in aqueous solutions.