Triple-Standard Hypochlorite Quantitative Array Enabled by Precise Stokes Shift Modulation in D-π-A Chemodosimeters

Abstract

The rational design of the D-π-A chemodosimeter with a significant Stokes shift is of great importance for enhancing the visualization of optical sensing signals. Here, three D-π-A fluorescent chemodosimeters with 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene) malononitrile (TCF) as the electron-withdrawing group are synthesized by precisely modulating the electron-releasing strength. By decreasing the ability of electron release, the electrophilicity of the recognition site is increased by 1.449 kcal/mol, the Stokes shift of the chemodosimeter is improved to 201 nm, and the sensing mode changes from fluorescence quenching to ratiometric fluorescence and finally to fluorescence on. Furthermore, the three D-π-A fluorescent chemodosimeters display superior sensing performance toward ClO^–, including low limits of detection (LOD, 37.0, 5.1, and 1.0 nM), rapid response (<5 s), and great selectivity in the presence of 16 kinds of interferents. Moreover, the practicality of the chemodosimeters is further validated by a portable triple-standard quantitative array detection platform, which can quantitatively detect ClO^– solutions. The proposed design and modulation strategy for chemodosimeters can provide a new pathway for the sensitive and visualized identification of oxidants and other hazardous chemicals.