title: Monitoring the presence of ionic mercury in environmental water by plasmon-enhanced infrared spectroscopy.
abstract: We demonstrate the ppt-level single-step selective monitoring of the presence of mercury ions (Hg²⁺) dissolved in environmental water by plasmon-enhanced vibrational spectroscopy. We combined a nanogap-optimized mid-infrared plasmonic structure with mercury-binding DNA aptamers to monitor in-situ the spectral evolution of the vibrational signal of the DNA induced by the mercury binding. Here, we adopted single-stranded thiolated 15-base DNA oligonucleotides that are immobilized on the Au surface and show strong specificity to Hg²⁺. The mercury-associated distinct signal is located apart from the biomolecule-associated broad signals and is selectively characterized. For example, with natural water from Lake Kasumigaura (Ibaraki Prefecture, Japan), direct detection of Hg²⁺ with a concentration as low as 37 ppt (37 × 10⁻¹⁰%) was readily demonstrated, indicating the high potential of this simple method for environmental and chemical sensing of metallic species in aqueous solution.
authors: WPI Center for Materials NanoArchitectonics-MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan. Hoang.ChungVu@nims.go.jp
authors: Chung V
authors: CV
authors: Hoang
authors: Makiko
authors: M
authors: Oyama
authors: Osamu
authors: O
authors: Saito
authors: Masakazu
authors: M
authors: Aono
authors: Tadaaki
authors: T
authors: Nagao