AbstractA colorimetric method is described for the determination of ferrous ion (Fe2+) with high sensitivity and selectivity. The method is based on catalytic etching of gold nanorod (NR). In an acid condition, Fe2+ reacts with H2O2 to produce superoxide radical (O2•−) that etches gold NRs from the low energy surface along the longitudinal direction preferentially. As a result, the changes in the absorption spectrum and color of gold NR can be measured and also can be detected visually. Under the optimal conditions, the assay has very low detection limit (13.5 nM) and a linear response in a concentration range of 75 to 1 μM. The method was applied to the determination of Fe2+ in spiked samples of fetal bovine serum and also transferred to a kind of test stripe for use in fast practical applications. A unique colorimetric sensing method is demonstrated for the colorimetric detection of Fe2+, again based on the oxidation of gold nanorods which leads to the blue-shift of the absorption. Graphical abstractA unique colorimetric sensing method was shown for the colorimetric detection of Fe2+. Fe2+reacts with H2O2 to generate superoxide radical that oxidize gold nanorods. This leads to a color change from blue-green to pink.

中文翻译：

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通过金纳米棒的形态转变比色测定亚铁离子

摘要 描述了一种高灵敏度和高选择性测定亚铁离子 (Fe2+) 的比色法。该方法基于金纳米棒 (NR) 的催化蚀刻。在酸性条件下，Fe2+ 与 H2O2 反应生成超氧自由基 (O2•-)，优先从低能表面沿纵向蚀刻金 NRs。因此，可以测量金 NR 的吸收光谱和颜色的变化，也可以通过视觉检测。在最佳条件下，该测定具有非常低的检测限 (13.5 nM)，并且在 75 至 1 μM 的浓度范围内具有线性响应。将该方法应用于胎牛血清加标样品中Fe2+的测定，并转移到一种用于快速实际应用的试纸条中。展示了一种独特的比色传感方法，用于比色检测 Fe2+，同样基于金纳米棒的氧化导致吸收蓝移。图形摘要展示了一种独特的比色传感方法，用于 Fe2+ 的比色检测。Fe2+ 与 H2O2 反应生成超氧自由基，氧化金纳米棒。这导致颜色从蓝绿色变为粉红色。