Optimization of Plasmonic U-Shaped Optical Fiber Sensor for Mercury Ions Detection Using Glucose Capped Silver Nanoparticles

Heavy metal contamination of water bodies has an adverse effect on human health and the environment even at very low concentrations. In this paper, we report U-shaped fiber optic probe coated with glucose capped silver nanoparticles (AgNPs) for label-free detection of mercury ions in aqueous solution. The reaction between glucose capped AgNPs and mercury ions resulted in a reduction in the plasmonic absorbance. The developed sensor probe was able to detect mercury ions concentration as low as 2 ppb, which is less than the World Health Organization acceptable limit for mercury ions in drinking water. The sensor probes displayed excellent selectivity towards mercury ions over other metal ions. Furthermore, the developed sensor probe was able to detect mercury ions down to 5 ppb in domestic tap water, i.e., selective detection of mercury even in real matrix having high concentration mixtures of various essential ions. The response of AgNPs coated sensor probe was found to be better than glucose capped gold nanoparticles and hollow gold-silver nanostructures coated fiber-optic probes.