A nanofiber-mat-based solid-phase sensor for sensitive ratiometric fluorescent sensing and fine visual colorimetric detection of tetracycline

Sensitive and real-time tetracycline (TC) monitoring method is of great significant for food safety and human health. Herein, a novel TC dynamic sensing mode based on a solid-phase nanofiber mat (NFM) sensor SP@COF/SDBS/PS NFM was constructed for the first time, where spiropyran-modified covalent organic framework (SP@COF) with red emissions (λem = 620 nm) was used as the reference fluorescence. Utilizing the adsorptive interaction between SP@COF/SDBS/PS NFM and TC, a PS-TC-SDBS supramolecular complex with a large rigid structure was formed, thus enhancing the fluorescence of TC (λem = 550 nm). The dynamic solid-phase sensing mode is unique and can be employed to selectively adsorb TC, with reduced interference by impurities in complex samples, and thus the sensitive TC ratiometric fluorescent sensing with a detection limit of 2.14 nM, and fine visual colorimetric detection with polychromatic wide color range (red-orange-yellow-green) was realized.