A colorimetric detection of Hg2+ based on gold nanoparticles synthesized oxidized N-methylpyrrolidone as a reducing agent

In this study, a gold nanoparticles colorimetric probe (AuNPs) with direct response to mercury ions (Hg 2+ ) were developed using treated N-methylpyrrolidone (NMP) and chloroauric acid (HAuCl 4 ) as precursors. NMP showed good reducibility after high temperature hydrolysis and could be used as reducing and stabilizing agent to synthesize AuNPs. The prepared AuNPs have obvious characteristic absorption peaks and appear wine-red. At the same time, it was found that the presence of Hg 2+ can cause the aggregation of AuNPs, increased the absorbance at 700 nm, and changed the color of the solution into blue-gray. This method is capable of sensitive and specific determination of Hg 2+ ranging from 1 to 30 μM, with the limit of detection (LOD) at 0.3 μM. The method showed good specificity for the determination of Hg 2+ and has the potential to be applied to Hg 2+ detection in sewage samples in the environment.