A fluorescent self-assembled monolayer film sensor with discriminatory power was specially designed and prepared by using pyrene as a reporting unit and a oligo(oxyethylene) unit as a hydrophilic spacer. The chemical attachment of pyrene moieties on the surface was verified by contact angle, XPS, UV-vis and fluorescence measurements. The fluorescence responses of the present film to nitroaromatic compounds (NACs) including picric acid, 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, and nitrobenzene were measured. Significantly, the present film exhibits cross-reactive responses to different NACs, and the array of fluorescence variation at four specific wavelengths (peaks for pyrene's monomer emission and excimer emission) provides a distinct recognition pattern for each NAC. The results from principle component analysis reveal that the present film has discriminatory power to identify structurally similar NACs. Moreover, the present film exhibits a high sensitivity, selectivity and reversibility towards NACs, and provides great potential in instrumentation and miniaturization. The use of multiple signals of a single film sensor based on fluorophore's different aggregation states (e.g., pyrene's monomer, distorted excimer, and perfect excimer in the present work) instead of an array of sensor elements provides a novel strategy for developing discriminatory materials and remarkably simplifies the process of identifying similar chemicals.
以
芘为报告单元,以低聚氧
乙烯单元为亲
水间隔物,专门设计和制备了一种具有分辨能力的荧光自组装单层膜传感器。通过接触角、XPS、紫外可见光和荧光测量,验证了
芘分子在表面的
化学附着。测量了薄膜对硝基芳香族化合物(
NAC)(包括
苦味酸、
2,4,6-三硝基甲苯、
2,4-二硝基甲苯和
硝基苯)的荧光反应。值得注意的是,本薄膜对不同的
NAC 具有交叉反应,在四个特定波长(
芘的单体发射峰和准分子发射峰)上的荧光变化阵列为每种
NAC 提供了独特的识别模式。原理成分分析的结果表明,本薄膜具有识别结构相似的
NAC 的能力。此外,本薄膜对
NAC 具有高灵敏度、选择性和可逆性,在仪器化和微型化方面具有巨大潜力。根据荧光团的不同聚集状态(如本研究中的
芘单体、扭曲准分子和完全准分子)使用单个薄膜传感器的多个信号来代替传感器元件阵列,为开发鉴别材料提供了一种新策略,并大大简化了鉴别类似
化学物质的过程。