High-Performance Ratiometric Fluorescence pH Sensor Based on HPTS-IP/TiO₂@THHM Sensing Film.

Area of Science:

• Materials Science
• Analytical Chemistry
• Chemical Sensing

Background:

• Developing accurate and rapid pH sensors is crucial for various scientific applications.
• Existing sensors often face limitations in sensitivity, response time, or stability.
• Ratiometric fluorescence sensing offers advantages in self-calibration and improved accuracy.

Purpose of the Study:

• To develop a high-performance ratiometric fluorescence pH sensor.
• To utilize a novel HPTS-IP/TiO2@THHM pH sensing film for enhanced performance.
• To establish a reliable method for pH prediction using spectral characteristics.

Main Methods:

• Fabrication of a pH sensing film embedding HPTS-IP hydrophobic ion pairs and TiO2 in a TEOS-HTES organic/inorganic hybrid matrix (THHM).
• Excitation of HPTS-IP using pulsed signals from two LEDs (404 nm and 454 nm).
• Development of a support vector regression (SVR) model for pH prediction based on fluorescence spectral characteristics.

Main Results:

• The fluorescence intensity ratio showed significant correlation with pH in the 6.0–9.0 range.
• The SVR model achieved a root mean square error (RMSE) of 0.180 and a correlation coefficient (R) of 0.999 for pH prediction.
• The sensor demonstrated a fast response time of 27 s, along with excellent reproducibility, reversibility, and stability.

Conclusions:

• The developed HPTS-IP/TiO2@THHM film is effective for ratiometric fluorescence pH sensing.
• The sensor exhibits high accuracy, rapid response, and robust stability.
• This sensor shows great potential for real-time pH monitoring applications.