A highly sensitive and selective turn-off fluorescence sensor for Fe3+ detection based on a terbium metal-organic framework

Abstract

A hydrothermal reaction of 1,3-di(3′,5′-dicarboxylphenyl)benzene (H4ddb) with Tb3+ gave out a metal-organic framework material (Tb-MOF). Tb-MOF emitted green fluorescence, assigned to the characteristic transitions 5D4→7FJ (J ​= ​6–3) of Tb3+. Screening detected metal cations indicated that only Fe3+ can completely quench the fluorescence of Tb-MOF in the twenty optional ions. The sensitivity test of Tb-MOF showed a linear response of I0/I ​= ​55.2061∙CFe3+ + 1.24077 in the CFe3+ range of 3.3 ​× ​10−4-0.033 ​mmol ​L−1 with LOD being 0.936 ​μM. Sixteen metal cations and four anions in the selectivity test did not influence the detection performances of Tb-MOF to Fe3+. The emission intensities of 5D4→7F5 at 545 ​nm of Tb3+ can basically be recovered during a four-time quenching-recovery cycle in the durability test. Tb-MOF is a quantitative turn-off fluorescence sensor to Fe3+ detection with high sensitivity and selectivity, rapid response and a certain durability.