Sensitive Detection of Auric and Sulphide ions using Hybrid Silver/Nitrogen-doped Carbon Nanoparticles

Abstract Hybrid Silver/Nitrogen-doped Carbon nanoparticles (i.e., Ag/NCNPs) have been explored as a spectrophotometric probe for the sensing of Au3+ and S2- ions in water, where the nitrogen-doped luminescent-carbon nanoparticles (NCNPs), derived from microwave pyrolysis of aqueous mixture of dextrose and urea, served as a reducing as well as a stabilizing agent for the Ag+ ions in-situ. The detection has been monitored by correlating the attenuation of the localized surface plasmon resonance (LSPR) band intensity of Ag/NCNPs at ∼ 416 nm in presence of Au3+ and S2- ions. Successive oxidation of Ag in the formulation, in presence of Au3+ ions in the system and subsequent in-situ formation of Au is assigned to the gradual diminution of the LSPR band. Likewise, depreciation of the LSPR band in the presence of S2- ions has been related to the depletion of Ag via the in-situ formation of Ag2S. The limit of detection (LOD) for Au3+ and S2- ions was found to be as low as 0.16 µM and 0.18 µM, respectively, and the presence of other common water-soluble ions making no significant contribution endorses the high sensitivity and selectivity of the probe.