2,2′,4,4′,6,6′-Hexanitrostilbene (HNS) is an explosive with better explosion performance than the well-known 2,4,6-trinitrotoluene (TNT). Surprisingly, unlike other nitroaromatic explosives, there are limited reports regarding the detection of the HNS, let alone sensing reports on surface residues. In this work, a multifunctional flexible SERS sensor was proposed for the indirect detection of HNS based on the transparent fixate gel pads. The sticky and flexible gel pad can effectively collect any HNS surface residues. The inherent amine groups within the gel pad of which the main ingredient is polyurethane can react with HNS to form the orange Meisenheimer-alike complex. The modification of Ag NPs with halide ions was screened for the best SERS performance. KI-modified-citrate-reduced Ag NPs showed selective but enormous SERS enhancement for the HNS derivative. The detection of HNS in the solution phase was explored, and a linear range of 0.01–25 ppm was achieved. The lowest detectable amount (LDA) of HNS was found to be 50 pg, making it one of the most sensitive methods in literature. It was successfully utilized for the HNS residues sensing on fingerprints and bags with LDAs of 5 and 200 ng, respectively. In addition, other explosives including TATB, LLM-105, RDX, HMX, FOX-7, and TNT were also examined to assess the selectivity of the fixate. It was found that the fixate showed excellent selectivity for HNS.

中文翻译：

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固定胶垫上的多功能柔性SERS传感器：爆炸性2,2'，4,4'，6,6'-六硝基二苯乙烯的捕获，推导和选择性象形图间接检测

2,2'，4,4'，6,6'-六硝基二苯乙烯（HNS）是一种炸药，具有比众所周知的2,4,6-三硝基甲苯（TNT）更好的爆炸性能。令人惊讶的是，与其他硝基芳族炸药不同，关于HNS检测的报道有限，更不用说对表面残留物的检测了。在这项工作中，基于透明固定胶垫，提出了一种多功能柔性SERS传感器用于HNS的间接检测。粘性且柔软的凝胶垫可有效收集任何HNS表面残留物。主要成分是聚氨酯的凝胶垫中的固有胺基可与HNS反应形成橙色的类似迈森海默的复合物。筛选了具有卤离子的Ag NPs修饰，以获得最佳的SERS性能。KI修饰的柠檬酸盐还原的Ag NPs对HNS衍生物表现出选择性但极大的SERS增强。探索了溶液相中HNS的检测方法，线性范围为0.01–25 ppm。发现HNS的最低可检测量（LDA）为50 pg，使其成为文献中最敏感的方法之一。它已成功用于指纹和袋子上HDA残留的检测，LDA分别为5和200 ng。此外，还检查了其他炸药，包括TATB，LLM-105，RDX，HMX，FOX-7和TNT，以评估固定液的选择性。发现固定液对HNS显示出优异的选择性。使其成为文献中最敏感的方法之一。它已成功用于指纹和袋子上HDA残留的检测，LDA分别为5和200 ng。此外，还检查了其他炸药，包括TATB，LLM-105，RDX，HMX，FOX-7和TNT，以评估固定液的选择性。发现固定液对HNS显示出优异的选择性。使其成为文献中最敏感的方法之一。它已成功用于指纹和袋子上HDA残留的检测，LDA分别为5和200 ng。此外，还检查了其他炸药，包括TATB，LLM-105，RDX，HMX，FOX-7和TNT，以评估固定液的选择性。发现固定液对HNS显示出优异的选择性。