A Ratiometric Multimode Optical Sensor for Highly Selective and Sensitive Detection of Ammonia by Hydrogen Bonding...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Ammonia is a vital industrial chemical and energy carrier.
• High ammonia levels in water pose significant environmental and ecological risks.
• Accurate and convenient monitoring of aqueous ammonia is crucial.

Purpose of the Study:

• To develop a self-calibrated multimode ratiometric optical sensor for aqueous ammonia detection.
• To evaluate the sensor's stability, sensitivity, selectivity, and response time.
• To investigate the sensing mechanism.

Main Methods:

• Fabrication of the Al-TCPP@MR optical sensor.
• Estimation of sensor performance using ratiometric fluorometry, colorimetry, and smartphone-based RGB analysis.
• Density Functional Theory (DFT) calculations to support the sensing mechanism.

Main Results:

• Achieved low detection limits (19.9 nM for fluorometry, 12.2 nM for colorimetry, 37.0 nM for RGB analysis).
• Demonstrated fast detection (5 min) with high recovery rates (97.3-102.8%) in various samples.
• Confirmed sensor stability, sensitivity, and selectivity.

Conclusions:

• The developed sensor provides an effective, rapid, and self-calibrated method for ammonia detection in complex samples.
• This work offers a promising approach for developing multimode sensors based on hydrogen bond regulation.