A self-calibrating dual-channel MOF-based fluorescent sensor for rapid and visual phosphate detection

Area of Science:

• Materials Science
• Analytical Chemistry
• Environmental Science

Background:

• Phosphate (Pi) sensing is crucial for environmental monitoring but faces challenges in signal stability and field deployability.
• Existing methods often lack the reliability and ease of use required for real-world applications.

Purpose of the Study:

• To develop a self-calibrating, dual-channel fluorescent sensor for rapid and visual detection of phosphate (Pi).
• To create a robust and field-deployable sensor based on a metal-organic framework (MOF) for environmental monitoring.

Main Methods:

• Fabrication of a dual-channel fluorescent sensor (9-AA@Eu-ZIF-8@TTA) using a modular host-guest and coordination assembly strategy.
• Utilizing a Pi-insensitive blue-emissive dye as an internal reference and a red-emissive Eu3+-TTA complex as the responsive channel.
• Employing a competitive coordination mechanism for Pi detection and ratiometric quantification.

Main Results:

• The sensor demonstrated a linear detection range of 0-80 μM for Pi with a low detection limit of 0.48 μM and a rapid response time of 0.5 min.
• Achieved excellent stability across a wide pH range (3-11) and high selectivity against interfering ions.
• Enabled visual discrimination of Pi levels and instrument-free quantitative readout via smartphone-based RGB analysis.

Conclusions:

• The developed MOF-based dual-channel sensor provides a reliable and practical solution for rapid and visual phosphate detection.
• The sensor's self-calibrating nature, stability, and field deployability address key limitations of existing methods.
• This work presents a versatile MOF design strategy for robust ratiometric fluorescent sensors integrating host-guest chemistry and coordination interactions.