Fluorophore molecule loaded in Tb-MOF for dual-channel fluorescence chemosensor for consecutive visual detection of bacterial spores and dichromate anion

Developing multifunctional luminescent switches for detecting various poisons are urgent given the continuous deterioration of the environment. Herein, a new porous fluorescent metal–organic framework [Tb2(TPTC)(DMA)4(NO3)2]n (HPU-25) was initially designed. Then, fluorophore molecule tris(2,2′-bipyridine) dichlororuthenium(II) hexahydrate (Ru(bpy)32+) was loaded onto HPU-25 by a simple post-synthesis strategy to prepare a new ratio fluorescence sensor Ru(II)@HPU-25. As a sensor, it can detect 2,6-pyridinedicarboxylic acid (DPA) content in real-time, with high sensitivity and selectivity, without being disturbed by probe concentration and environment. Evident changes in fluorescence color and intensity are observed in distinguishing DPA contents. In addition, after detecting DPA, it can be used for consecutive visual detection of dichromate anion (Cr2O72−) in water. This multifunctional fluorescence sensor could make up for the defects of single fluorescence and single function of the traditional fluorescence sensor by using the dual strategies of ratio sensing and cascade sensing. Interestingly, DPA and Cr2O72− in samples can be visually detected rapidly in real-time through the chroma acquisition APP on smartphone. More importantly, we also designed the combination of two logic gate operations for sensing the two targets. In the poison detection in daily life, these intelligent applications of fluorescence sensors have a broad development space.