Multiple fluorescent sensing responses of a 2D framework structure towards explosive: Synthesis, characterization and sensing performance

Abstract

Abstract In the following work, we reported an optical sensing platform with dual sensing channels for picric acid (PA), named as RS@EuBTC. This sensing platform consisted of supporting matrix derived from luminescent rare earth MOF and a rhodamine-derived sensing probe. By means of XRD, IR, TGA, absorption, emission and excitation spectra, RS@EuBTC s composite structure was confirmed. Its rhodamine absorption component was enhanced by increasing PA concentration in visible region, showing colorimetric sensing behavior. Its rhodamine emission component was enhanced obviously by PA as well, but its Eu emission component was slightly quenched by PA, showing ratiometric fluorescent sensing response towards PA. Linear sensing response towards PA was found for both sensing channels with LOD as low as 4.8 μM. RS@EuBTC depicted good selectivity towards PA over interferents. Its sensing mechanism was convinced as the combination of rhodamine emission turn on effect triggered by PA s protons and Eu emission turn off effect caused by an electron transfer procedure initiated by PA s electron-pulling effect. The novelty of RS@EuBTC localized at its possibility of naked eye detection and dual sensing channels with good selectivity.