An ultra-low detection limit Fe 3+ optical fiber fluorescent sensor based on a anti-B 18 H 22 derivative with aggregation-induced emission enhancement

A fluorescent Fe3+ probe ((C10H7NO2)2B18H20, M1) by introducing two isoquinoline-1-carboxylic acid group into the 6,9-position of anti-B18H22 was designed and synthesized. The structure of M1 was investigated by 1H NMR, MS, FT-IR and theoretical calculation, and its optical properties were characterized with UV-Vis and PL. M1 showed aggregation induced emission enhancement(AIEE) properties in THF/H2O solution, and exhibited excellent selectivity toward Fe3+ in THF/H2O (v/v, ƒw=95%) solution with a detection limit of 1.93×10-5 M. The interaction mechanism of probes with Fe3+ was attributed to the involvement of intermolecular charge transfer (ICT) process. Furthermore, a optical fiber fluorescent Fe3+ sensor based on M1 sensing film was developed, the detection limit of the optical fiber Fe3+ fluorescent sensor could be improved to13.8pM, the ultra-low detection limit is superior to most reported fluorescent probes (or sensors) towards Fe3+. This method has the advantages of high sensitivity, anti-interference and easy to operate, and has great potential in the field of the analysis of environmental and biological samples.