Development of Binary Coassemblies for Sensitively and Selectively Detecting Gaseous Sarin

The low sensitivity and poor selectivity of fluorescence sensors for real gaseous sarin detection greatly hinder their real-world applications. In this work, we report the development of a novel fluorophore with an active N-H vibration in the benzimidazole group for the sensitive detection of gaseous sarin. We demonstrate that the interactions between the nucleophilic fluorine atom in sarin and the electrophilic hydrogen atom in the benzimidazole group of the fluorophore can restrict the N-H vibration to yield sensitive fluorescence-enhancing responses. On the basis of this mechanism, the experimental and theoretical limits of detection for gaseous sarin can reach as low as 50 and 4.8 ppb, respectively. We further coassemble this fluorophore with another two D-A fluorophores containing different acceptor groups and use the resulting coassemblies as sensor array members to obtain access to differential combined responses to gaseous sarin compared with various interferents, including diethylchlorophosphate and acids. This two-member sensor array proves to be capable of detecting trace sarin in complex environments, demonstrating its potential applications in the real world.

Automated summary

This study develops a novel fluorophore with an active N-H vibration in the benzimidazole group for sensitive detection of gaseous sarin. By restricting the N-H vibration through interactions between the nucleophilic fluorine atom in sarin and the electrophilic hydrogen atom in the benzimidazole group, sensitive fluorescence-enhancing responses are achieved, with experimental and theoretical limits of detection reaching as low as 50 and 4.8 ppb, respectively. Coassembling this fluorophore with two other D-A fluorophores containing different acceptor groups, a sensor array is formed to obtain differential combined responses to gaseous sarin compared with various interferents. This two-member sensor array demonstrates the potential for detecting trace sarin in complex environments.