Synergistic effect of inner filtering effect and host-guest interaction based on β-cyclodextrin fluorophore for promoted 4-nitrophenol detection

Efficient detection of 4- nitrophenol (4-NP) organic pollutant is always a very important issue due to the rapid development of chemical industry and the abuse of pesticides and so on. Here, we designed and synthesized a novel supramolecular fluorescent probe , 4-[4-(acetylamino)styryl]-1-cyclodextrin pyridinium p-toluenesulfonate (ASPT-β-CD), for the selective and sensitive detection of 4-NP. The introduction of β-CD not only improves the water solubility of probe and can also be used as a host to encapsulate 4-NP. In alkaline aqueous solution, the absorption spectrum of 4-NP overlaps the excitation spectrum of ASPT-β-CD and suggests that an internal filtration effect occurs between them. We explored the possible response mechanism and speculated that the high selectivity and high sensitivity were derived from the synergistic effect of inner filtering effect and host-guest interaction. Benefiting from the synergistic effect, the proposed sensor ASPT-β-CD displayed significant "turn-off" after adding 4-NP, while showing a fast response to 4-NP within 2 min and low LOD about 0.01 μM. In addition, this method has been successfully applied to the determination of 4-NP in lake water samples, indicating that the obtained ASPT-β-CD has great practical application potential in the environmental field.