A sensitive localized surface plasmon resonance sensor for determining mercury(II) ion using noble metal nanoparticles as probe.

The noble metal nanoparticles (NPs), including gold nanorods (AuNRs), gold nanospheres (AuNSs) and silver nanoplates (AgNPTs), were synthesized and Tween 20 stabilized NPs (Tween 20-NPs) were used as the probes for determining Hg(2+). Hg(2+) was determined based on the strong affinity between Au (Ag) and Hg. Hg(2+) was reduced to Hg in the presence of sodium borohydride. Hg interacts with the NPs and the diameter of the NPs decreases with the increase of Hg(2+) concentration, which causes the shift in absorption peak of Tween 20-NPs. The peak shifts are linearly related to Hg(2+) concentrations. Compared with AuNSs and AgNPTs, when the AuNRs was used, the sensitivity for determining Hg(2+) was higher. The developed method shows a good selectivity for Hg(2+) and can be applied to the determination of Hg(2+) in water samples.