Colorimetric sensing of mercury ions using green synthesized silver nanoparticles from Trigonella foenum (Linnaeus)

Abstract

Mercury ion sensing is an essential technology in water polluted countries especially India, China, south east Asian countries etc. This type of technology heavily relies on nano-sensing with silver nanoparticles. Colorimetric sensors are optical sensors that change color in response to an external input. A colorimetric sensor was developed to detect hazardous mercury ions in water. Silver nanoparticles will lose its UV–Vis absorption intensity when combined with mercury ions. Plant extract of Trigonella foenum (Linnaeus) was used to prepare silver nanoparticles in this study. Having a cubic form and an average crystallite size of 27.24 nm, the silver nanoparticles are widely distributed. Nanoparticles were found to be crystalline and has a cubic phase of geometry, as demonstrated by XRD and SEM investigation. Using biosynthesized Ag nanoparticles, we demonstrate very sensitive and specific colorimetric detection of the mercury ion (Hg2+).