The efficient fluorescence probe for haloacetic acids detection based on the Eu(III) complex constructed by...

A dual-emission fluorescence probe for sensitive determination of haloacetic acids (HAAs) was fabricated based on the Eu(III) complex (DDM-Phen-Eu), while dehydroabietic amine (DDM) and 1,10-phenanthroline (Phen) served as the ligands. FTIR, UV-vis, WAXD, SEM, elemental analysis, ESI-MS, and XPS measurements were employed to disclose the coordination structure of DDM-Phen-Eu. Based on the study of the Huang-Rhys factors and the Judd-Ofelt parameters, the introduction of DDM would decrease the reorganization energy, stabilize the coordinate structure, and improve the fluorescence quantum yield of DDM-Phen-Eu up to 90.68%. Due to the hydrophobic property of DDM component, water has been excluded from the coordinate structure of DDM-Phen-Eu, which generated the fluorescence from both Phen and the Eu(III) ions of DDM-Phen-Eu in aqueous solution. The fluorescence intensities of DDM-Phen-Eu remained stable in acidic, neutral, and alkaline solutions, even with the addition of NaCl. Halogen bond between the halogen atoms of HAAs and the N atoms of Phen component, accompanied with the coordination bond between the carboxyl group of HAAs and the Eu(III) ions, induced the charge transfer from DDM-Phen-Eu to HAAs and suppressed the fluorescence of DDM-Phen-Eu. Fluorescence quenching endowed DDM-Phen-Eu with sensitivity in the detection of HAAs with the concentrations range of 0 ∼ 1.78 μM for chloroacetic acid (CA), 0 ∼ 0.875 μM for bromoacetic acid (BA), and 0 ∼ 0.758 μM for iodoacetic acid (IA), respectively. The limits of detections for CA, BA, and IA were 0.151, 0.087, and 0.077 μM, respectively.