Triple-Interpenetrated Lanthanide-Organic Framework as Dual Wave Bands Self-Calibrated pH Luminescent Probe

Area of Science:

• Materials Science
• Chemistry
• Environmental Science

Background:

• Accurate pH monitoring is crucial for assessing water quality and reaction processes.
• Developing highly sensitive luminescent ratiometric pH sensors remains a significant challenge.

Purpose of the Study:

• To design and synthesize a novel luminescent lanthanide-organic framework (V104) for sensitive and self-calibrated pH sensing.
• To investigate the dual emission properties of V104 for detecting both H+ and OH- ions.
• To enhance the sensor's recyclability by incorporating magnetic nanoparticles.

Main Methods:

• Synthesis of a triple-interpenetrated luminescent lanthanide-organic framework {[Eu(PPTA)0.5(NO3)(DMF)2]·H2O}n (V104) using an amphoteric ligand (H4PPTA).
• Characterization of V104's luminescent properties, including dual emission peaks at 390 and 480 nm.
• Encapsulation of magnetic γ-Fe2O3 nanoparticles within V104 to create a recyclable sensor (γ-Fe2O3@V104).

Main Results:

• V104 demonstrated high stability in various solvents and pH conditions.
• The dual emission peaks of V104 selectively responded to OH- and H+ ions.
• The sensor achieved high sensitivity, with a response of 403.2% per pH for OH- and 129.5% per pH for H+.
• The magnetic γ-Fe2O3@V104 sensor was successfully recycled at least four times.

Conclusions:

• V104 represents the first self-calibrated ratiometric pH sensor utilizing two distinct responsive wavebands for separate H+ and OH- detection.
• The γ-Fe2O3@V104 composite shows significant potential for practical applications in real-time pH monitoring of water bodies.