Food wastage due to spoiling is a global economic issue and contributes to over-farming and overfishing with real environmental consequences. Smart food packaging is a promising solution to this problem, the concept of which is to incorporate responsive sensors that allow direct monitoring of the gasses released from the decay of food into a label that provides a visual indicator to the consumer as to whether the food is fresh or has spoiled. Here we report two dicyanovinyl-fluorene-benzothiadiazole-based fluorescent compounds, K12 and K12b, both of which showed rapid response to biogenic amines via two independent mechanisms. When primary alkyl amines were present in solution, they underwent an aza-Michael addition with the dicyanovinyl group of the sensing material, resulting in a rapid colour change. The reaction products of K12 and K12b with primary amines showed a decrease and increase in the fluorescence quantum yield, respectively, enabling a unique dual-sensor array with turn-off/turn-on response. In addition, fluorescence quenching via photoinduced hole transfer was observed in the solid-state sensor films with a wide range of primary, secondary and tertiary amines, enabling rapid and sensitive detection of amine vapours. Finally, we show as proof-of-concept that the fluorescence quenching response of sensing films was observable at cadaverine concentrations relevant to the food industry.

中文翻译：

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基于双氰胺基的荧光传感器，用于双机制胺传感

腐败造成的食物浪费是全球性的经济问题，导致过度养殖和过度捕捞，并带来实际的环境后果。智能食品包装是解决该问题的一种有前途的解决方案，其概念是将可直接监控从食品腐烂释放出的气体的响应式传感器整合到标签中，该标签可为消费者提供有关食品是否为食品的直观指示新鲜或变质。这里，我们报告两个基于二氰基芴苯并噻二唑荧光化合物，K12和K12b，两者都显示出对生物胺的快速响应通过两种独立的机制。当伯烷基胺存在于溶液中时，它们会与传感材料的双氰基乙烯基进行氮杂-迈克尔加成反应，导致颜色快速变化。K12和K12b与伯胺的反应产物分别显示出荧光量子产率的降低和增加，从而实现了具有关/开响应的独特双传感器阵列。此外，通过荧光猝灭在具有多种伯，仲和叔胺的固态传感器膜中观察到光诱导的空穴转移，从而能够快速灵敏地检测胺蒸气。最后，我们证明了在与食品工业相关的尸胺浓度下可观察到传感膜的荧光猝灭响应，这是概念验证。