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Press ReleasePress Release 2013

High-sensitivity Detection of Dilute Ionic Mercury in Environmental Water

Early-stage Detection of Toxic Element by Infrared Spectroscopy-

8 May, 2013

Nanosystem Photonics Group (Group Leader, Tadaaki NAGAO) in MANA has developed a new methodology to detect trace amounts of mercury from lacustrine water by using infrared light with sensitivity more than ten times higher than existing optical sensing techniques using visible light.

They have developed a method to detect trace amounts of mercury selectively by combining infrared spectroscopy with nano-gapped gold islands coated by molecules which shows specific binding to mercuric ions. By utilizing localized plasmonic field concentrated at the nano-scale gaps, bulk water signal can be reduced efficiently. And thanks to the strong enhancement of the electromagnetic field at these gaps, the signal associated with the mercury trapping of the coating material (DNA aptamer) inside these gaps can be enhanced dramatically. The group has demonstrated that the detection limit of mercury solved in environmental water (from Lake Kasumigaura) can be as low as 40 ppt by using commercial Fourier transform infrared spectrometer. This sensitivity is one order of magnitude smaller than the environmental standard in Japan.

The technique is expected to be conveniently applied to the quality test of environmental water. Also, the methodology is expected for contributing to the detection of other types of environmental pollutions as well as to the industrial waste water treatment.


Fig. 1: Water specimen was taken from the Lake Kasumigaura and mixed with trace amounts of ionic mercury. Detecting element is composed of Au substrate with high-density of nano-scale gaps coated with mercury-binding molecules (DNA aptamers) with high specificity. When the mercury is trapped by the mercury-binding molecule, the infrared spectrum is changed at a specific frequency and mercury is detected.

Further information


Chung V. Hoang, Makiko Oyama, Osamu Saito, Masakazu Aono, and Tadaaki Nagao, "Monitoring the Presence of Ionic Mercury in Environmental Water by Plasmon-Enhanced Infrared Spectroscopy", Scientific Reports, 3(2013), 1175.

World Premier International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS)

Contact information

For more detail about research

Nano-System Photonics Group, Nano-System Organization Unit, MANA, NIMS
Group Leader Tadaaki Nagao
E-mail: <NAGAO.Tadaakinims.go.jp>

For general inquiry

Public Relations Office, NIMS
Email: prnims.go.jp
TEL:+81-29-859-2026 FAX:+81-29-859-2017

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