A novel boronic acid-based fluorescent sensor for selectively recognizing Fe 3+ ion in real time.

Boronic acid provides faster fluorescence response to Fe 3+ compared to other reported sensors, which is critical for continuous dynamic detection. Herein, we reported a novel boronic acid-based sensor 4 that could recognize Fe 3+ ion in real time. After 10 equiv. of Fe 3+ ion (1 mM) was added, the fluorescence of sensor 4 was immediately quenched by 96%. While other ions, including Ba 2+ , Ca 2+ , Cr 2+ , Cd 2+ , Co 2+ , Cs 2+ , Cu 2+ , Fe 2+ , K + , Li + , Mg 2+ , Mn 2+ , Na + , Ni 2+ or Zn 2+ , respectively, did not change the fluorescence significantly. Further tests indicated that the high selectively sensing Fe 3+ ion benefits from the two boronic acid functionalities in the structure. Moreover, interference experiments showed this sensor has an excellent anti-interference ability. In addition, we performed binding activity test in rabbit plasma and other real samples for practical applications, obtaining similar results. And the thin layer loading sensor 4 was also successfully applied to recognize Fe 3+ ion among various ions. Therefore, 4 may serve as a potential sensor for continuous monitoring and detecting Fe 3+ ion in real time.