Spectrophotometric determination of mercury(II) ion using gold nanorod as probe

A simple method for sensing mercury in aqueous solutions based on localized surface plasmon resonance was developed. Gold nanorods are aggregated in the presence of dithiothreitol. However, the strong coordination of Hg2+ with dithiothreitol results in a stable HgS covalent bond and inhibits the aggregation of the gold nanorods. The potential factors affecting the performance of the detection of Hg2+ were carefully optimized. Under the optimal conditions, the differences of ratios of absorbances at two wavelengths are directly proportional to the Hg2+ concentrations in the range of 1–50 nmol/L. The limit of detection is 0.42 nmol/L. The developed method shows a good selectivity for Hg2+ and can be applied to the determination of Hg2+ in water samples.