Simultaneous pH and temperature measurements using pyranine as a molecular probe

Area of Science:

• Biophysics
• Analytical Chemistry
• Microfluidics

Background:

• Concentration and temperature gradients are common in small fluid compartments like cells and microfluidic devices.
• Accurate characterization of these gradients is crucial for understanding these systems.
• Existing fluorescence methods often have coupled temperature and concentration measurements, limiting accuracy.

Purpose of the Study:

• To develop a method for simultaneous measurement of pH and temperature.
• To overcome the limitations of existing techniques where concentration measurements depend on temperature and vice versa.

Main Methods:

• Utilized the blinking of the fluorescent pH indicator pyranine.
• Employed fluorescence correlation spectroscopy to measure protonation and deprotonation rates.
• Established a unique relationship between these rates and pH/temperature values.

Main Results:

• Demonstrated a novel method for simultaneous pH and temperature measurement.
• Showed that the rate-pH-temperature relationship is sensitive to other acid-base molecules in solution.
• Identified influence of ionic strength and buffer composition on the measurement.

Conclusions:

• The developed method allows for simultaneous and accurate measurement of pH and temperature.
• The technique provides a valuable tool for studying complex micro-scale environments.
• Further research is needed to account for solution composition effects for precise quantification.