A novel neodymium-based porphyrin metal-organic frameworks for dual-mode detection of iron ions

Abstract

Effective identification of iron ions (Fe3+) in the environment and food supplements is essential but challenging. Though traditional single-mode fluorescent sensing methods are user-friendly and sensitive, their accuracy is prone to being affected by external factors. Therefore, it is necessary to propose multi-mode probes to detect Fe3+ accurately and effectively in various media. In this study, a novel neodymium-centered lanthanide porphyrin metal-organic framework (NTMNs)-based sensor was designed for dual-mode detection of Fe3+ in fluorescence and UV. NTMNs was rapidly synthesized by microwave synthesis in just 10 min using the lanthanide metal neodymium (Nd) as the metal center and 4,4,4,4-(Porphine-5,10,15,20-tetrayl) tetrakis (TCPP) as the ligand. A host-guest effect and electrostatic attraction were observed between NTMNs and Fe3+, which resulted in the weakening of both fluorescence intensity and UV absorption of NTMNs, enabling the NTMNs-based Fe3+ sensor with self-calibrating detection in two modes in 5 min. Moreover, Fe3+ was successfully measured in real water samples with recoveries ranging from 89.8% to 105.4%. Furthermore, by comparing the detection results of Fe3+ contents in iron supplements, we confirmed that the detection difference between the proposed sensor and the standard inductively coupled plasma-mass spectrometry method is negligible. The feasibility and validity of the NTMNs-based sensor for the detection of Fe3+ were demonstrated. In conclusion, this method exhibits a promising application for rapidly detecting Fe3+ in dual-mode (UV, fluorescence), which is self-calibrated with high accuracy and sensitivity for environmental pollution, water quality monitoring, and food safety.