Ratiometric Fluorescent pH Sensing with Carbon Dots: Fluorescence Mapping across pH Levels for Potential Underwater...

Area of Science:

• Materials Science
• Environmental Science
• Analytical Chemistry

Background:

• Ocean acidification and industrial pH monitoring necessitate robust, affordable sensors.
• Ratiometric fluorescence sensing using carbon dots offers a promising solution due to their cost-effectiveness and stability.
• Developing novel carbon dots is key to identifying optimal pH-sensitive candidates.

Purpose of the Study:

• To synthesize and characterize novel carbon dots for pH sensing applications.
• To evaluate the pH sensitivity of synthesized carbon dots across a range of pH values.
• To identify carbon dots with optimal ratiometric fluorescence properties for accurate pH measurement.

Main Methods:

• Five types of carbon dots were synthesized using a simple solvothermal method.
• Fluorescence properties of carbon dots were analyzed across pH 5-9 and excitation/emission ranges.
• Ratiometric analysis was performed using emission band ratios at specific wavelengths.

Main Results:

• All five synthesized carbon dots demonstrated pH sensitivity in both UV and visible light spectra.
• Carbon dots derived from m-phenylenediamine exhibited ratiometric properties at four excitation wavelengths.
• Optimal ratiometric sensing was achieved at 475 nm excitation, with good linearity between pH 6-9.

Conclusions:

• Carbon dots synthesized from m-phenylenediamine are highly suitable for ratiometric pH sensing.
• The developed carbon dots offer a cost-effective and robust alternative for environmental and industrial pH monitoring.
• This research advances the development of advanced fluorescent pH sensors.