过氧化物爆炸物现场检测用新型比率型碳纳米荧光探针的构筑研究

In recent years, peroxide-based explosives which can be easily prepared and are difficult to detect, have been increasingly used by the terrorists because nitro explosives have been faced with stronger supervision and easier to be found all over the world. Fluorescent detection of explosives is an important tool to safeguard public security. Current fluorescent probes detecting peroxide-based explosives are often disturbed by nitro explosives because of special physical and chemical properties of peroxide-based explosives. Meanwhile, detection sensitivity and naked-eyes visibility will been greatly improved when the change of intensity based on single wavelength will be replaced by ratiometric detection. In this study, it will be the first time to link boron dipyrromethene (Bodipy) with carbon dots by chemical bond. We will study the design principles, preparation methods and ratiometric response mechanism to develop carbon-dot-based ratiometric fluorescent probe for on-site detection of peroxide-based explosives. The benzil and BODIPY will serve as recognition group and fluorophore of novel probe, respectively, so that it will avoid the interference by nitro explosives. Meanwhile, the nanoprobe based on carbon dots has low toxicity, good dispersity and high photostability. In addition, “green off - red on” ratiometric response between carbon dots and BODIPY based on FRET will provide higher sensitivity and visibility. In a word, we will develop novel ratiometric fluorescent nanoprobe to improve the selectivity, sensitivity and visibility of on-site detection of peroxide-based explosives, and to further meet public environmental monitoring.

近年来，世界各国加强了对硝基爆炸物的监管与检测，以致恐怖分子转向易于自制且难于检测的过氧化物爆炸物。爆炸物的荧光检测是维护公共安全的重要手段，由于过氧化物爆炸物理化性质的特殊性，导致现有荧光探针难以抵御硝基爆炸物干扰，且基于单一波长的强度变化，检测灵敏度和裸眼可视度将有较大提升空间。本项目拟首次将氟硼二吡咯甲川（BODIPY）键合于碳点上，研究其设计原理、制备方法与比率型响应机制，获得过氧化物爆炸物现场检测用新型碳纳米探针。该探针以苯偶酰为新型识别基团，BODIPY为光谱响应基团，可避免硝基爆炸物的干扰；同时，基于碳点的纳米探针具有低毒性、高分散性和光稳定性；另外，探针中碳点与BODIPY产生FRET机理的“绿暗-红亮”比率型响应，将具有更高的检测灵敏度和裸眼可视度。总之，本项目拟发展新型比率型碳纳米探针，提升过氧化物爆炸物现场检测的选择性、灵敏度及可视度等，以满足公共环境监测的现实需求。

近年来，恐怖爆炸袭击事件频发，反恐防爆相关方法和技术引起了世界各国的广泛关注。过氧化爆炸物作为新型炸药因其原料易得、合成简单、爆炸威力大的特点，被恐怖分子广泛用于恐怖爆炸袭击活动。然而，过氧化爆炸物既没有紫外吸收也没有荧光发射，且其化学结构同时缺乏硝基和芳香烃基，以致其分析检测面临极大的挑战。目前，基于荧光法的分子探针具有灵敏度高、选择性好、操作简单、携带方便等优点，逐渐发展为爆炸物检测领域的重要方法之一。过氧化爆炸物含有过氧化基团（-O-O-），而过氧化基团不稳定，易光解产生过氧化氢（H2O2），且H2O2也是合成过氧化爆炸物的必要原料。通过对过氧化爆炸物的信号分子H2O2的分析检测有望实现对过氧化爆炸物的有效监测与预警。因此，本研究以对H2O2具有高选择性的苯偶酰为识别基团，以具有光稳定好、摩尔消光系数大等优点的二氟化硼二吡咯甲烷（BODIPY）为荧光团，设计合成了两种新型H2O2荧光探针4-(4-硝基苯偶酰基)-氟硼二吡咯甲烷（p-NBBD）和3-(4-硝基苯偶酰基)-氟硼二吡咯甲烷（m-NBBD），并采用高分辨质谱、核磁共振氢谱、碳谱等分析手段表征了它们的化学结构，进而考察了探针的光谱性质，及其对H2O2的荧光检测性能。新型荧光探针自身荧光很弱，荧光量子产率仅为0.008–0.010；当与H2O2响应之后其荧光大幅增强，荧光量子产率达到0.43–0.56，可基于光诱导电子转移（d-PET）机理发出很强的绿色荧光。探针及其H2O2衍生产物具有很好的光稳定性，连续光照3 h，探针的荧光基本保持不变，它们的H2O2衍生产物的荧光强度仍分别保持在94%及86%以上。同时，探针对H2O2具有较高的选择性，不易受活性小分子、硝基爆炸物及硝基爆炸物的降解产物的干扰。而且，荧光探针对H2O2具有较快的响应速率（30s）和很好的检测灵敏度（0.94ppb），并成功用于H2O2裸眼可视的现场快速检测。此外，新型探针对TATP类的过氧化爆炸物具有很好的传感检测性能，稳定性好，选择性强，对TATP固体粉末检出限在微克级。总之，本研究针对过氧化爆炸物的分析检测设计和制备了新型的荧光探针，发展了对过氧化爆炸物具有很好检测性能的荧光分析方法，为过氧化爆炸物的检测与预警提供了新的检测技术与手段。