National Agenda Research Division, Korea Institute of Science & Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.
University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon, 34113, Republic of Korea.
Mikrochim Acta. 2021 Mar 20;188(4):132. doi: 10.1007/s00604-021-04772-7.
Concave gold nanocubes are viable optical nanoprobes for the determination of nitrite ions. Herein, a novel approach was developed, based on the measurement of localized surface plasmon resonance absorption. The addition of nitrite ions selectively induced the etching of concave gold nanocubes, abrading the sharp vertices to spherical corners, which resulted in blue-shifted absorption accompanied by a color change from sapphire blue to light violet. The mechanism of selective etching of concave gold nanocube tips was elucidated by using X-ray photoelectron spectroscopy and atom probe tomography. The optimized detection of NO via the concave gold nanocube-based probe occurred at pH 3.0 and in 20 mM NaCl concentration at 40 °C. The absorption ratios (A/A) were proportional to the NO concentrations in the range 0.0-30 μM, with a detection limit of 38 nM (limit of quantitation of 0.12 μM and precision of 2.7%) in tap water. The highly selective and sensitive colorimetric assay has been successfully applied to monitor the nitrite ion concentrations in spiked tap water, pond water, commercial ham, and sausage samples.
凹面金纳米立方体是测定亚硝酸盐离子的可行光学纳米探针。在此，提出了一种新的方法，基于局域表面等离子体共振吸收的测量。亚硝酸盐离子的加入选择性地诱导凹面金纳米立方体的蚀刻，将尖锐的顶点磨成球形角，导致吸收蓝移，同时颜色从蓝宝石蓝变为浅紫色。通过 X 射线光电子能谱和原子探针断层扫描阐明了凹面金纳米立方体尖端选择性蚀刻的机制。通过基于凹面金纳米立方体的探针对 NO 的优化检测在 pH 3.0 下和在 40°C 时在 20 mM NaCl 浓度下进行。吸收比 (A/A) 与 0.0-30 μM 范围内的 NO 浓度成正比，在自来水中的检测限为 38 nM（定量限为 0.12 μM，精密度为 2.7%）。这种高选择性和灵敏的比色测定法已成功应用于监测加标自来水中、池塘水中、商业火腿和香肠样品中亚硝酸盐离子的浓度。
