Development of LSPR-Based Optical Fiber Sensor Employing Graphene Oxide (GO) for the Detection of Mercury in Water

Heavy metal contamination can adversely affect water bodies, harming the environment and human health even at very low concentrations. This study describes a U-shaped fiber-optic probe coated with gold nanoparticles (AuNPs) and graphene oxide (GO) as the sensing material for label-free detection of mercury ions in aqueous solution. LSPR technique is exploited to develop the optical fiber sensor for mercury detection. GO is coated over the gold nanoparticles plated core of the optical fiber. The transmittance of the LSPR spectra increases with increase in the mercury concentration, due to the refractive index change in the surrounding medium. The proposed mercury sensor responds linearly over a range of 1–50 ppm mercury concentration, with a sensitivity of 0.178 nm/ppm Hg2+ ion concentration and the limit of detection is 0.14 ppm. The proposed sensor can be a valuable tool for monitoring and detecting mercury ions in water to protect human health and the environment.