Hybrid Membrane of Agarose and Lanthanide Coordination Polymer: a Selective and Sensitive Fe3+ Sensor

A new hybrid membrane was prepared by a facile method based on a highly luminescent lanthanide coordination polymer and agarose. The soft membrane was characterized by FT-IR, PXRD, SEM and luminescence. It is found that the soft membrane is a highly selective and sensitive sensor, among 19 metal ion solutions of Fe 3+ , Mg 2+ , Li + , Ca 2+ , Zn 2+ , Cu 2+ , Ba 2+ , Mn 2+ , Ru 3+ , Cr 3+ , Ag + , Sr 2+ , Cd 2+ , Na + , Ni 2+ , Pb 2+ , Fe 2+ , Hg 2+ and Ca 2+ , only Fe 3+ quench the luminescence. The sensing results can be distinguished by the naked eye in daylight or by irradiation of a portable UV light at the scene. Mechanism studies reveal the sensing is due to the decomposition of the coordination polymer 1 which induced by slow permeation of Fe 3+ . Further studies found anions of BO 3 − , CO 3 2 − , H 2 PO 4 − , Br − , Cl − , ClO 4 − , H 2 PO 4 − , I − , IO 3 − and NO 3 − will not quench the luminescence of the hybrid membrane, which imply that other anions in water would not disturb the detection result.