Facile and rapid detection of iodide ion (I^–) has a substantial impact on nuclear chemistry, environmental monitoring, and other fields. Here, we report a new method for visual detection of I^– at the single-microbubble level. This assay utilizes the total internal reflection of single O₂ microbubble at the O₂ microbubble–glass interface to produce the evanescent wave, which is imaged by a dark-field microscope. The diameter of the single O₂ microbubble in the H₂O₂ aqueous solution increases after introduction of I^–, thanks to its catalytic ability toward H₂O₂ decomposition. With this assay, I^– is quantitatively determined based on the diameter change of the single O₂ microbubble, along with micromolar level sensitivity, and the corresponding dynamic ranges from 0.08 to 1 mM. Impressively, this visual assay possesses high selectivity owing to the specific catalytic activity of I^–, and it is successfully applied for detection of real water samples, showing satisfactory recovery rates. Our study opens up a single O₂ microbubble analytical platform with a high spatial resolution because of the small size of the microbubble, which holds great promise in chemical and environmental applications.

中文翻译：

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单氧微泡的全内反射目测碘离子

轻便和快速检测碘离子（I ^- ）对核化学，环境监测等领域产生重大影响。在这里，我们报告的我目视检测的新方法^-在单微气泡水平。该测定法利用单个O ₂微气泡在O ₂微气泡-玻璃界面的全内反射来产生the逝波，该e逝波由暗场显微镜成像。引入I ^–后，H ₂ O ₂水溶液中单个O ₂微气泡的直径增加，这是由于其对H ₂ O _2的催化能力分解。通过这种测定，可以根据单个O ₂微气泡的直径变化以及微摩尔水平的灵敏度以及从0.08到1 mM的相应动态范围来定量确定I ^–。令人印象深刻的是，由于I ^–的特定催化活性，该目测法具有很高的选择性，并且已成功用于检测真实水样，显示出令人满意的回收率。由于微气泡的小尺寸，我们的研究打开了一个具有高空间分辨率的O ₂微气泡分析平台，这在化学和环境应用中具有广阔的前景。