Selective Detection of Trace Cr3+ in Aqueous Solution by Using 5,5′-Dithiobis (2-Nitrobenzoic acid)-Modified Gold Nanoparticles

A simply prepared gold nanoparticle-based sensor, 5,5'-dithiobis(2-nitrobenzoic acid) (DTNBA)-modified gold nanoparticles, was prepared to explore the sensitive and selective detection of metal ions using a colorimetric technique. The selective detection of trace levels (93.6 ppb) Cr3+ in aqueous solution was achieved over 15 other metal ions. The functionalized gold nanoparticles became aggregated in solution in the presence of Cr3+ by an ion-templated chelation process, which caused an easily measurable change in the extinction spectrum of the particles and provided an inherently sensitive method for Cr3+ detection in aqueous solution.