Colorimetric mercury detection with enhanced sensitivity using magnetic-Au hybrid nanoparticles

Due to the neural toxicity of mercury, there is a need for the development of on-site detection systems for Hg2+ monitoring. To this end, a new colorimetric mercury detection probe, Fe3O4@SiO2@Au (magnetic-Au; Mag-Au) hybrid nanoparticles, has been developed. The Au on the surface of Mag-Au is an indicator of Hg2+, which forms an AuHg alloy (amalgam) on their surface (Mag-Au@Hg), with excellent peroxidase-like activity. The oxidation of 3,3 ',5,5 '-tetramethylbenzidine by Mag-Au@Hg resulted in a color change of the indicator solution, which was enhanced with increasing Hg2+ concentration. Mag-Au can be used to detect Hg2+ at nanomolar concentrations. Additionally, magnetic separation can be used to easily purify and concentrate the Mag-Au@Hg from samples, and thus avoid interference from unwanted residues or colored samples. The feasibility of Mag-Au for Hg2+ detection was tested with an artificial urine solution and it can be used to detect Hg2+ in various real samples, such as river water, seawater, food, and biological samples.

Automated summary

Due to the neural toxicity of mercury, a new colorimetric mercury detection probe, Fe3O4@SiO2@Au (magnetic-Au; Mag-Au) hybrid nanoparticles, has been developed for on-site detection of Hg2+. The presence of Hg2+ forms an AuHg alloy (amalgam) on the surface of Mag-Au, with excellent peroxidase-like activity. The oxidation of a substrate leads to a color change, allowing the detection of Hg2+ at nanomolar concentrations. Magnetic separation can be used to purify and concentrate the Mag-Au@Hg from samples, avoiding interference from unwanted residues or colored samples. The feasibility of Mag-Au for Hg2+ detection has been validated with artificial urine solution and can be applied to various real samples.