The nucleophilic substitution reaction between 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) and –NH₂ groups on amino-functionalized carbon dots (CDs) produces a novel carbon dot-based hybrid, CDs@NBD for short. In addition to the characteristic fluorescence emission of carbon dots at λ_ex/λ_em = 360/443 nm, the CDs@NBD hybrid gives rise to new photoluminescence at λ_ex/λ_em = 460/544 nm, which is significantly quenched by p-phenylenediamine (PPD) via static quenching. This provides a novel sensing approach for fluorometric detection of PPD with CDs@NBD as a probe. A linear calibration graph is obtained within two concentration ranges of 0.1–1.0 μmol L⁻¹ and 1.0–10.0 μmol L⁻¹, along with a detection limit of 56 nmol L⁻¹ and a RSD of <3% (at 1.0 μmol L⁻¹). The common coexisting species in environmental and biological sample matrices cause no obvious interferences on the detection of PPD. The colour change of the CDs@NBD hybrid solution with the variation in PPD concentration also facilitates visual detection of PPD, which further demonstrates promising applications in environmental and biological sample analysis.

中文翻译：

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碳点与4-氯-7-硝基-2,1,3-苯并恶二唑的杂合物，用于选择性检测对苯二胺†

4-氯-7-硝基-2,1,3-苯并恶二唑（NBD-Cl）与氨基官能化碳点（CD）上的–NH ₂基团之间的亲核取代反应产生了一种新型的基于碳点的杂化体CDs @简称NBD。除了在碳点的特征荧光发射λ _EX / λ _EM =四百四十三分之三百六nm时，光盘@ NBD混合生出新的光致发光在λ _EX / λ _EM =五百四十四分之四百六纳米，它是由显著猝灭p -苯二胺（PPD）通过静态淬火。这为以CDs @ NBD为探针的PPD荧光检测提供了一种新颖的传感方法。线性校准曲线图的0.1〜1.0微摩尔1L双浓度范围内获得^-1和1.0-10.0微摩尔大号^-1，用56纳摩尔升的检测限沿着^-1在1.0微摩尔L和<3％RSD一个（^-1）。环境和生物样品基质中常见的共存物种不会对PPD的检测产生明显干扰。CDs @ NBD混合溶液的颜色随PPD浓度的变化而变化，也有利于PPD的视觉检测，这进一步证明了在环境和生物样品分析中有希望的应用。