Smart gold nanosensor for easy sensing of lead and copper ions in solution and using paper strips

Abstract

A smart gold nanosensor, Au–TA–DNS is designed that can rapidly detect very low concentrations of Pb²⁺ and Cu²⁺ ions. The nanosensor develops a visible blue colour in solution and on paper strips, because of the formation of nanoparticle aggregates upon binding with metal ions. Due to the presence of dansyl fluorophore, Au–TA–DNS also exhibits significant fluorescence quenching following Pb²⁺ and Cu²⁺ binding in aqueous medium, which is proportional to the concentration of ions. Both colorimetric and fluorometric analyses are very much selective for lead and copper ions with a detection limit of ≤10.0 ppb. The paper based sensing method has the advantage of cost-effectiveness and would be useful for wide range of field-test applications such as water quality monitoring process.