Ultrasensitive detection of lead (Ⅱ) based on the disaggregation of a polyether bridged squaraine fluorescent probe

摘要

In this work, a novel fluorescent chemosensor, based on a polyether bridged squaraine, has been developed for the detection of Pb~(2+) and gives excellent sensitivity and selectivity using a cation-induced disaggregation strategy. This probe exhibited a specific "turn on" fluorescent response to Pb~(2+) with a detection limit of 1.70 × 10~(-8) M, and the identification for Pb~(2+) was not impacted by competing ions such as Na~+, Li~+, K+, Mg~(2+), Ca~(2+), Sr~(2+), Co~(2+), Ni~(2+), Zn~(2+), Ag~+, Cd~(2+), and Hg~(2+) Due to the high binding ability of the polyether bridged ionophore toward Pb~(2+), the disaggregation process could be trigged by the formation of squaraine-Pb~(2+) complex, resulting in a fast fluorescent release. The sensing mechanism has been confirmed by NMR, IR, and dynamic light scattering experiments. Further research shows that this novel fluorescent probe can be applied in the fast detection of Pb~(2+) in urine and shrimp samples.