基于金纳米棒刻蚀比色法检测铁、铜离子

采用种子生长法制备金纳米棒(AuNRs)以构建光学传感器，用于Fe³⁺和Cu²⁺的高选择性快速可视化检测。在酸性环境中，Fe³⁺和Cu²⁺通过与KI溶液反应，将I-氧化成I2。I2刻蚀AuNRs，导致其纵向表面等离子体共振(LSPR)吸收峰蓝移，从而实现对Fe³⁺和Cu²⁺的检测。结果表明，反应温度为50℃时，添加0.8 mL 0.1 mol·L^-1 HCl、2 mL AuNRs生长液和20 mmol·L^-1 KI溶液，与2 mL 500 μmol·L^-1 Fe³⁺或30 μmol·L^-1 Cu²⁺反应25或90 min，可将AuNRs刻蚀至LSPR吸收峰消失。该方法对Fe³⁺和Cu²⁺检测具有高选择性和准确性，对于Fe³⁺、Cu²⁺共存体系的检测，可通过加入适量F-与Fe³⁺生成配合物[FeF₆]^3-完成对Fe³⁺的化学掩蔽，消除Fe³⁺的干扰，实现共存体系中Cu²⁺的准确检测。

Detection of iron and copper ions based on gold nanorod etching colorimetry

In an acidic environment, Fe³⁺ and Cu²⁺ reacted with KI solution to oxidize I^- to I₂, and I₂ was used to etch Au nanorods (AuNRs) to produce a blue shift of the longitudinal surface plasmon resonance (LSPR) absorption peak of AuNRs to achieve the detection of Fe³⁺ and Cu²⁺. At a reaction temperature of 50℃, 0.8 mL HCl (0.1 mol· L^-1), 2 mL KI (20 mmol· L^-1), and 2 mL AuNRs solution were added in 2 mL 500 μmol·L^-1 of Fe³⁺ or 30 μmol·L^-1 of Cu²⁺ solution, and the Fe³⁺ or Cu²⁺ solution could etch AuNRs until the LSPR absorption peak of AuNRs disappeared after 25 or 90 min. The concentrations of Fe³⁺ and Cu²⁺ had a good linear relationship with the LSPR absorption peak shift of AuNRs, and the R² was above 0.99. This method has excellent selectivity and accuracy for the detection of Fe³⁺ and Cu²⁺, with a maximum error of only 0.69% and 2.6%, respectively. For the detection of Fe³⁺ and Cu²⁺ coexistent system, the addition of an appropriate amount of F^- in Fe³⁺ solution to form a complex[FeF₆]^3- can chemically mask Fe³⁺, which can eliminate the interference of Fe³⁺ in the coexistence system. The results showed that in a Cu²⁺ concentration range of 0-20 μmol·L^-1, the LSPR absorption peaks of AuNRs before and after the addition of Fe³⁺-F^- masking system were blue-shifted 217 and 210 nm, respectively. There was a good linear relationship between the Cu²⁺ concentration and the LSPR absorption peak shift of AuNRs, and the R² was above 0.99. It can be concluded that the accurate detection of Cu²⁺ in the mixed system can be achieved by chemically masking the Fe³⁺ in the coexisting ions.