In this work, we introduce the use of 4-dimethylamino-4′-nitrostilbene (DANS) fluorescent dye for applications in the detection and analysis of microplastics, an impendent source of pollution made of synthetic organic polymers with a size varying from less than 5 mm to nanometer scale. The use of this dye revealed itself as a versatile, fast and sensitive tool for readily discriminate microplastics in water environment. The experimental evidences herein presented demonstrate that DANS efficiently absorbs into a variety of polymers constituting microplastics, and its solvatochromic properties lead to a positive shift of the fluorescence emission spectrum according to the polarity of the polymers. Therefore, under UV illumination, microplastics glow a specific emission spectrum from blue to red that allows for a straightforward polymer identification. In addition, we show that DANS staining gives access to different detection and analysis strategies based on fluorescence microscopy, from simple epifluorescence fragments visualization, to confocal microscopy and phasor approach for plastic components quantification.

中文翻译：

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使用 4-二甲氨基-4'-亚硝基芪溶剂致变色荧光鉴定微塑料

在这项工作中，我们介绍了 4-二甲氨基-4'-亚硝基芪 (DANS) 荧光染料在微塑料检测和分析中的应用，微塑料是一种由尺寸小于 5 的合成有机聚合物制成的迫在眉睫的污染源毫米到纳米级。这种染料的使用表明它是一种多功能、快速和灵敏的工具，可以轻松区分水环境中的微塑料。本文提供的实验证据表明，DANS 有效地吸收到构成微塑料的各种聚合物中，并且其溶剂致变色特性导致荧光发射光谱根据聚合物的极性发生正移。因此，在紫外线照射下，微塑料发出从蓝色到红色的特定发射光谱，可以直接识别聚合物。此外，我们展示了 DANS 染色提供了基于荧光显微镜的不同检测和分析策略，从简单的落射荧光片段可视化到共聚焦显微镜和用于塑料成分量化的相量方法。