AbstractA microwave-assisted hydrothermal method was employed to prepare thymine-modified graphitic carbon nitride quantum dots (T-gCNQDs) which are shown to be a novel fluorescent nanoprobe for Hg(II). They exhibit excellent optical properties (blue emission with a fluorescence quantum yield of 46%) and water solubility. The incorporation of thymine into the gCNQDs results in an enhancement in photoluminescence properties. It is found that fluorescence, best measured at excitation/emission wavelengths of 350/445 nm, is much more strongly quenched by Hg(II) compared to the thymine-free nanoprobe. The quenching is highly selective even in the presence other metal ions. This is ascribed to the formation of T-Hg(II)-T base complexes. Fluorescence drops linearly in the 1.0 to 500 nM Hg(II) concentration range, and the limit of detection is 0.15 nM. The method was applied to the determination of Hg(II) in spiked samples of tap and pond water. Recoveries were found to be >95%, thus demonstrating the practical applicability of the assay. Graphical abstractA microwave-assisted hydrothermal route was employed to prepare thymine-functionalized graphitic carbon nitride QDs (T-gCNQDs). A selective fluorescence quenching mechanism occurred between T-gCNQDs and Hg(II) due to thymine functionalization. T-gCNQDs was utilized to detect Hg(II) in real samples.

中文翻译：

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微波辅助合成胸腺嘧啶功能化石墨氮化碳量子点作为汞（II）的荧光纳米探针

摘要 采用微波辅助水热法制备了胸腺嘧啶修饰的石墨氮化碳量子点 (T-gCNQDs)，该量子点是一种新型的 Hg(II) 荧光纳米探针。它们表现出优异的光学特性（蓝色发射，荧光量子产率为 46%）和水溶性。将胸腺嘧啶掺入 gCNQD 导致光致发光特性的增强。结果表明，与不含胸腺嘧啶的纳米探针相比，在 350/445 nm 激发/发射波长下测量的荧光强度被 Hg(II) 淬灭得更强。即使在其他金属离子存在的情况下，猝灭也是高度选择性的。这归因于 T-Hg(II)-T 碱复合物的形成。荧光在 1.0 至 500 nM Hg(II) 浓度范围内线性下降，检测限为 0.15 nM。该方法用于测定自来水和池塘水中加标样品中的 Hg(II)。发现回收率 > 95%，从而证明了该测定的实际适用性。图形摘要采用微波辅助水热法制备胸腺嘧啶功能化石墨氮化碳量子点（T-gCNQDs）。由于胸腺嘧啶功能化，T-gCNQDs 和 Hg(II) 之间发生了选择性荧光猝灭机制。T-gCNQDs 用于检测实际样品中的 Hg(II)。由于胸腺嘧啶功能化，T-gCNQDs 和 Hg(II) 之间发生了选择性荧光猝灭机制。T-gCNQDs 用于检测实际样品中的 Hg(II)。由于胸腺嘧啶功能化，T-gCNQDs 和 Hg(II) 之间发生了选择性荧光猝灭机制。T-gCNQDs 用于检测实际样品中的 Hg(II)。