Fluorescence/Electrochemical Dual-Mode Sensor Based on a Nickel Metal-Organic Framework

Area of Science:

• Materials Science
• Analytical Chemistry
• Environmental Science

Background:

• 2,4,6-trinitrophenol (TNP) is a hazardous explosive and pollutant.
• Highly sensitive and selective detection methods for TNP are crucial for environmental monitoring and public safety.
• Metal-organic frameworks (MOFs) offer tunable properties for advanced sensing applications.

Purpose of the Study:

• To develop a novel dual-mode sensor material for efficient TNP detection.
• To investigate the sensing performance of the Ni-MOF CUST-986 in both fluorescence and electrochemical modes.
• To elucidate the detection mechanism and assess the practical applicability of the developed sensor.

Main Methods:

• Synthesis and characterization of the nickel metal-organic framework [Ni(tatrz)1.5(5-MIA)·H2O] (CUST-986).
• Dual-mode sensing experiments utilizing fluorescence quenching and electrochemical detection.
• Characterization techniques including powder X-ray diffraction, UV-vis spectroscopy, DFT calculations, and fluorescence lifetime measurements.
• Environmental sample analysis to evaluate practical performance and stability.

Main Results:

• CUST-986 exhibited highly selective TNP detection with a fluorescence quenching constant (Ksv) of 1.676 × 10^5 M^-1 and a low limit of detection (LOD) of 69.3 nM.
• The electrochemical detection mode achieved a TNP LOD of 0.48 μM.
• Real environmental sample tests demonstrated spike recovery rates of 80.3-93.6%, indicating good practical potential.
• The detection mechanism involving electron transfer and inner filter effects was elucidated.

Conclusions:

• The developed bifunctional Ni-MOF sensor (CUST-986) offers a highly efficient and sensitive dual-mode platform for TNP detection.
• The sensor demonstrates excellent selectivity, low detection limits, and good stability, making it suitable for real-world applications.
• This work provides a promising new solution for environmental monitoring and public safety through advanced MOF-based sensing technology.